- Los Angeles, California, United States
Demian Willette
Loyola Marymount University, Biology, Department Member
Research Interests:
Genetic stock structure is atypical in tuna species, with most species demonstrating geographically‐broad, panmictic populations. Here, genetic data suggest a distinct pattern for Thunnus tonggol across the Indo‐Pacific region. The... more
Genetic stock structure is atypical in tuna species, with most species demonstrating geographically‐broad, panmictic populations. Here, genetic data suggest a distinct pattern for Thunnus tonggol across the Indo‐Pacific region. The genetic variation in the coastal tuna T. tonggol sampled from across the South China Sea was examined using the highly variable mitochondrial DNA displacement loop (D‐loop) gene region. One hundred and thirty‐nine specimens were sampled from four locations in Indonesia, Vietnam and the Philippines. Phylogenetic reconstruction of genetic relationships revealed no significant ɸST statistics and hence no population structure within the South China Sea. However, subsequent analysis with sequence data from coastal northwest India infers discrete genetic stocks between the Indian Ocean and the South China Sea. Consistent with previous genetic analyses of tuna species in the Indo‐Pacific, the findings in this study infer no population structure within each basin, but rather show a significant partitioning across the wider region. Furthermore, these results have implications for the management of the commercially valuable Thunnus tonggol across national boundaries, and thus requiring collaboration among countries to ensure its sustainable use
Research Interests:
Research Interests:
ABSTRACT Morphology, meristics, and molecular genetics tools were used to determine the species level identification of the most commonly landed sardine species in the Philippines. Results from this study indicated that the historical and... more
ABSTRACT Morphology, meristics, and molecular genetics tools were used to determine the species level identification of the most commonly landed sardine species in the Philippines. Results from this study indicated that the historical and widely applied nomenclature of the Indian oil sardine, Sardinella longiceps, is incorrect and that this species is instead the Bali sardinella Sardinella lemuru. Developing an effective strategy for managing one of the Philippines most important commodity sardine species first requires accurate identification of this species. Results of this study provide needed information that is now being applied to emerging management policies.
Research Interests:
Sardinella tawilis (Clupeiformes: Clupeidae) is the world s only freshwater sardine and is endemic to Taal Lake, Batangas, Philippines. Locally referred to as tawilis, it is the most dominant and commercially important fishery of the... more
Sardinella tawilis (Clupeiformes: Clupeidae) is the world s only freshwater sardine and is endemic to Taal Lake, Batangas, Philippines. Locally referred to as tawilis, it is the most dominant and commercially important fishery of the lake, but in recent years severe depletion has been apparent in catch records. A proposed management strategy favors the demarcation of a new fish sanctuary; however, it is unclear which area in the lake is appropriate for conservation. This study applied molecular genetics tools to describe the phylogeographic pattern of tawilis across Taal Lake to determine whether a single or multiple stocks exist; and which location supports the highest level of haplotype diversity to assist in the placement of the fish sanctuary. One hundred and forty-one specimens were collected from eight fishing locations around Taal Lake. Fish were indentified, the DNA extracted using a Chelex-resin method, amplified for the ribosomal 16S and mtDNA Cyt B gene regions, and sequenced. Sequences were cleaned using the genetics software Sequencher v4.8 (GeneCode Corp.), aligned and phylogenetic trees visualized in MEGA v5 (Tamura et al., 2007), and assessed for haplotype composition by location using DnaSP v5.1 (Librado and Rozas, 2009). Results for the haplotype frequency analysis showed two dominant haplotypes to be common at most or all fishing locations, with northern basin locations of the lake supporting a higher mean and absolute number of haplotypes than locations in the southern basin. Yet no fishing ground contained more than 45% of the total observed haplotype diversity and thus no ideal location for a new fish reserve could be identified. Rather, all specimens formed a single clade with no significant divergence between individuals from the eight fishing grounds for both genetic markers (Fig. 1). This suggests that all tawilis within Taal Lake are part of a single, panmictic stock. Given the mixing population, we suggest that a closed season be considered as an alternative strategy in managing the world s only freshwater sardine fishery
Research Interests:
National and global priorities are increasingly focused on the concurrent marine fisheries challenges of food security, illegal fishing, and declining fisheries resources. Molecular genetics and electronic monitoring technologies can... more
National and global priorities are increasingly focused on the concurrent marine fisheries challenges of food security, illegal fishing, and declining fisheries resources. Molecular genetics and electronic monitoring technologies can advance solutions to these challenges, particularly in fisheries surveillance and seafood traceability, and a growing number of studies continues to validate the utility of these tools. What is needed next is guidance to support their wider, more conventional adoption and implementation, either complementary to or in the absence of government policies. Here, we synthesize discussion held during the Borchard Foundation Colloquium held in July 2022 in Missillac, France on modernizing global fisheries with emerging technologies. Our aim is to provide perspectives to scientists, resource managers, and policy makers of emerging monitoring technologies, summarize the utility of these technologies in fisheries, and conclude with how the objective to modernize ...
Research Interests:
Research Interests:
The European eel (Anguilla anguilla) has declined by over 90% since the early 1980s and has been listed as critically endangered. Yet, despite strict export bans from the European Union, the European eel is still sold illegally in many... more
The European eel (Anguilla anguilla) has declined by over 90% since the early 1980s and has been listed as critically endangered. Yet, despite strict export bans from the European Union, the European eel is still sold illegally in many countries. Efforts to monitor the trade of European eels have been primarily concentrated in Asian markets where concerningly high rates of European eel have been reported. Comparably fewer studies have assessed the identities of eel samples from the United States (US), despite the obvious implications for eel conservation. To address this knowledge gap, we purchased 137 eel products (134 freshwater eels and three saltwater eels) from grocers, sushi bars, and restaurants in nine states across the US from 2019 to 2021. Seven samples (5.2%) labeled as freshwater eels (or “unagi”) were identified as European eels using a combination of mitochondrial (cytochrome b) and nuclear (18S rRNA) restriction digestion assays, a fast and inexpensive molecular tool ...
Research Interests:
The evolution of networks is constrained by spatial properties of the environment; a characterization that is true in both biological and built networks. Hence built networks such as urban streets can be compared to biological networks to... more
The evolution of networks is constrained by spatial properties of the environment; a characterization that is true in both biological and built networks. Hence built networks such as urban streets can be compared to biological networks to reveal differences in efficiency and complexity. This study assessed foraging networks created by the slime-mold Physarium polycephalum on proportional 3D-printed topographic maps of metropolitan city of Los Angeles, California. Rapidly-generated isomorphic solutions were found to be consistently and statistically shorter than existing roadways in system length. Slime mold also allocated resources to supporting key nodes, analogous to how heavy traffic flows through major intersections. Further, chemical deterrents inhibited exploration of slime mold in selected areas and allows for testing of network redundancy and system resilience, such as after an earthquake or wildfire
Research Interests:
The global COVID-19 pandemic has forced many educators to move their courses to the online environment with little time to adjust. It especially affected undergraduate biology laboratory courses that rely on on-campus facilities to... more
The global COVID-19 pandemic has forced many educators to move their courses to the online environment with little time to adjust. It especially affected undergraduate biology laboratory courses that rely on on-campus facilities to provide students with meaningful laboratory-type experiences. Here we describe a multisession, at-home, and hands-on laboratory activity that utilizes yogurt culturing to explore microbiology concepts. We also summarize the findings of 219 undergraduate students who successfully performed this lab remotely. In small virtual groups, students learned how to make yogurt at home, formulate a testable hypothesis, run an experiment on conditions necessary for yogurt fermentation, analyze experimental results, and present their results to peers in an oral scientific talk. Practical considerations include the use of low-cost and accessible materials, low-tech yet effective quantification approaches, and online note-taking and data management tools to coordinate g...
Research Interests:
Research Interests:
Hands-on, inquiry-based laboratory activities are excellent opportunities to introduce first-year undergraduate students to the lab environment and to catalyze new interest in topics they may not yet know or be as enthusiastic about... more
Hands-on, inquiry-based laboratory activities are excellent opportunities to introduce first-year undergraduate students to the lab environment and to catalyze new interest in topics they may not yet know or be as enthusiastic about studying. We describe a multisession introductory laboratory activity that couples the research areas of medicinal drug discovery and plant biology. Selecting from a diversity of native California plants and broadly recognized medicinal plants, students learn and apply an assortment of basic phytochemical assays, analyze preliminary data, and then formulate hypothesis-driven follow-up experiments. Working in small groups, students develop shared project management and collaboration skills, and present activity results to peers in multiple modalities. Furthermore, we summarize findings from 163 student experiments using 29 plant species into an Instructor's Resource Table to facilitate guiding students through their preliminary and follow-up experimen...
Research Interests:
The nature and strength of interactions between native and invasive species can determine invasion success. Species interactions can drive, prevent or facilitate invasion, making understanding the nature and outcome of these interactions... more
The nature and strength of interactions between native and invasive species can determine invasion success. Species interactions can drive, prevent or facilitate invasion, making understanding the nature and outcome of these interactions critical. We conducted mesocosm experiments to test the outcome of interactions between Halophila stipulacea, a seagrass that invaded the Mediterranean and Caribbean Seas, and native seagrasses (Cymodocea nodosa and Syringodium filiforme, respectively) to elucidate mechanisms explaining the successful invasions. Mesocosms contained intact cores with species grown either mixed or alone. Overall, in both locations, there was a pattern of the invasive growing faster with the native than when alone, while also negatively affecting the native, with similar patterns for shoot density, aboveground and belowground biomass. In the Caribbean, H. stipulacea increased by 5.6 ± 1.0 SE shoots in 6 weeks when grown with the native while, when alone, there was a ne...
Research Interests:
The global COVID-19 pandemic has forced many educators to move their courses to the online environment with little time to adjust. It especially affected undergraduate biology laboratory courses that rely on on-campus facilities to... more
The global COVID-19 pandemic has forced many educators to move their courses to the online environment with little time to adjust. It especially affected undergraduate biology laboratory courses that rely on on-campus facilities to provide students with meaningful laboratory-type experiences. Here we describe a multisession, at-home, and hands-on laboratory activity that utilizes yogurt culturing to explore microbiology concepts. We also summarize the findings of 219 undergraduate students who successfully performed this lab remotely. In small virtual groups, students learned how to make yogurt at home, formulate a testable hypothesis, run an experiment on conditions necessary for yogurt fermentation, analyze experimental results, and present their results to peers in an oral scientific talk. Practical considerations include the use of low-cost and accessible materials, low-tech yet effective quantification approaches, and online note-taking and data management tools to coordinate group work and provide informal and formal assessment.
Research Interests:
Research Interests:
The nature and strength of interactions between native and invasive species can determine invasion success. Species interactions can drive, prevent or facilitate invasion, making understanding the nature and outcome of these interactions... more
The nature and strength of interactions between native and invasive species can determine invasion success. Species interactions can drive, prevent or facilitate invasion, making understanding the nature and outcome of these interactions critical. We conducted mesocosm experiments to test the outcome of interactions between Halophila stipulacea, a seagrass that invaded the Mediterranean and Caribbean Seas, and native seagrasses (Cymodocea nodosa and Syringodium filiforme, respectively) to elucidate mechanisms explaining the successful invasions. Mesocosms contained intact cores with species grown either mixed or alone. Overall, in both locations, there was a pattern of the invasive growing faster with the native than when alone, while also negatively affecting the native, with similar patterns for shoot density, aboveground and belowground biomass. In the Caribbean, H. stipulacea increased by 5.6 ± 1.0 SE shoots in 6 weeks when grown with the native while, when alone, there was a net loss of −0.8 ± 1.6 SE shoots. The opposite pattern occurred for S. filiforme, although these differences were not significant. While the pattern in the Mediterranean was the same as the Caribbean, with the invasive grown with the native increasing shoots more than when it grew alone, these differences for shoots were not significant. However, when measured as aboveground biomass, H. stipulacea had negative effects on the native C. nodosa. Our results suggest that a seagrass that invaded two seas may drive its own success by both negatively affecting native seagrasses and benefiting from that negative interaction. This is a novel example of a native seagrass species facilitating the success of an invasive at its own cost, providing one possible mechanism for the widespread success of this invasive species.
Research Interests:
Marine fisheries are an important source of food security, livelihood, and employment for coastal communities around the world. However, their sustainability is undermined in contexts of weak institutions at multiple levels of governance,... more
Marine fisheries are an important source of food security, livelihood, and employment for coastal communities around the world. However, their sustainability is undermined in contexts of weak institutions at multiple levels of governance, illegal fishing, and poor seafood traceability. Ecuador and Peru share historical, ecological, social, and economic features in terms of marine affairs, conservation, and fisheries development, and therefore face similar challenges to sustainability. The goal of this synthesis is to provide an overview of the aspects in common and to highlight the relevance of bi-national cooperation in scientific research in times of transformation of seafood systems into more sustainable ones. We show that there are important fishery resources in common, and potentially many more that are
Research Interests:
The European eel (Anguilla anguilla) has declined by over 90% since the early 1980s and has been listed as critically endangered. Yet, despite strict export bans from the European Union, the European eel is still sold illegally in many... more
The European eel (Anguilla anguilla) has declined by over 90% since the early 1980s and has been listed as critically endangered. Yet, despite strict export bans from the European Union, the European eel is still sold illegally in many countries. Efforts to monitor the trade of European eels have been primarily concentrated in Asian markets where concerningly high rates of European eel have been reported. Comparably fewer studies have assessed the identities of eel samples from the United States (US), despite the obvious implications for eel conservation. To address this knowledge gap, we purchased 137 eel products (134 freshwater eels and three saltwater eels) from grocers, sushi bars, and restaurants in nine states across the US from 2019 to 2021. Seven samples (5.2%) labeled as freshwater eels (or ''unagi'') were identified as European eels using a combination of mitochondrial (cytochrome b) and nuclear (18S rRNA) restriction digestion assays, a fast and inexpensive molecular tool for seafood identification that can identify hybrids between European eels (A. anguilla) and American eels (A. rostrata). No hybrids between European and American eels were found and all seven samples identified with restriction digestion as European eels were confirmed by sequencing of cytochrome b and 18S rRNA. Frequency of European eels in US markets did not significantly correlate with state or retail type. Although illegal eel exports are likely reaching US consumers, the frequency of European eel samples in this study of the US market is much lower than found in other non-European countries.
Research Interests:
Research Interests:
Research Interests:
Rhinolophus affinis sensu lato is a widespread bat species in South and Southeast Asia which shows considerable geographical variation in its morphology, echolocation call frequencies and genetics. The taxonomic status of the taxon in the... more
Rhinolophus affinis sensu lato is a widespread bat species in South and Southeast Asia which shows considerable geographical variation in its morphology, echolocation call frequencies and genetics. The taxonomic status of the taxon in the Sundaic subregion remains uncertain however as the limited studies to date have been largely based on morphology. The aim of the present study was to determine the taxonomic status of subspecific forms recognized in the subregion and to evaluate phylogeographic distinctiveness between those occurring in Borneo and the Malay Peninsula using genetic, morphological and acoustic datasets. Two forms were confirmed: R. a. nesites from Borneo and R. a. superans from the peninsula. The previous recognition of a population from southernmost Sumatra as R. a. superans was not supported, however, as this form is likely R. a. affinis. Genetic divergence between these three forms is rather deep and is estimated to have occurred during the arid climatic period of...
Research Interests:
FIG. 8. Bacula of R. affinis from the Sundaic Subregion in lateral view (l), ventral view (v) and dorsal view (d); Sarawak, northwestern Borneo (A — TK152217); Lampung, southwestern Sumatra (B — MZB31501); Narathiwat, southern Malay... more
FIG. 8. Bacula of R. affinis from the Sundaic Subregion in lateral view (l), ventral view (v) and dorsal view (d); Sarawak, northwestern Borneo (A — TK152217); Lampung, southwestern Sumatra (B — MZB31501); Narathiwat, southern Malay Peninsula (C — IS120124.1). Scale = 1 mm
FIG. 1. Sample localities and echolocation frequencies of R. affinis in the Sundaic subregion. M = Peninsular Malaysia, Sa = Sarawak, S = Sumatra, and T = Thailand. Abbreviations for localities are given in the methods and materials. The... more
FIG. 1. Sample localities and echolocation frequencies of R. affinis in the Sundaic subregion. M = Peninsular Malaysia, Sa = Sarawak, S = Sumatra, and T = Thailand. Abbreviations for localities are given in the methods and materials. The grey shading indicates the Sundaic biogeographic subregion following Woodruff (2010), green (zone A) and orange (B) shadings are the echolocation zones recognized in the Malay Peninsula. Dashed arrows indicate type localities and subspecies names, solid arrows indicate the transition zone of biota within the Malay Peninsula, dashed lines indicate the echolocation frequencies (min–max), and the two-headed arrows indicate the echolocation frequencies (min–max) as a whole from each echolocation zone. Note: the northern boundary of the Sundaic subregion is sometimes placed at the Isthmus of Kra (e.g., Lekagul and McNeely, 1988 and Corbet and Hill, 1992)
The spread of invasive species is a major component of global ecological change and how and when to manage particular species is a difficult empirical question. Ideally, these decisions should be based on the specific impacts of invading... more
The spread of invasive species is a major component of global ecological change and how and when to manage particular species is a difficult empirical question. Ideally, these decisions should be based on the specific impacts of invading species including both their effects on native competitors and how they may or may not play similar roles in broader ecosystem functioning. Halophila stipulacea is an invasive seagrass currently spreading through the Caribbean, and as seagrasses are foundation species, the effects of invasion have the potential to be particularly far-reaching. To evaluate the impacts of H. stipulacea we quantified spread and potential for displacement of native seagrasses as well as the effects of invasion on multiple ecosystem processes, particularly resource support for higher trophic levels and habitat creation. Long-term monitoring suggested that H. stipulacea likely displaces some native seagrasses (Syringodium filiforme and Halodule wrightii), but not others. Halophila stipulacea had lower N and protein levels and higher C:N ratios than native seagrasses, and as such is a poorer quality resource for consumers. We also observed significantly lower consumption of H. stipulacea than the native S. filiforme but limited differences compared to Thalassia testudinum. We found H. stipulacea created a more nutrient limited environment than T. testudinum and there were significantly distinct invertebrate assemblages in native- and invasive-dominated seagrass beds, but no difference in species richness or invertebrate biomass. These results suggest that the spread of H. stipulacea would impact a variety of ecological processes, potentially restructuring seagrass ecosystems through both direct impacts on environmental conditions (e.g., nutrient availability) and indirect food web interactions.
Research Interests:
Abstract Seagrass meadows evolved in the presence of disturbances and have a wide variance in recovery rate that largely follow a trajectory of re-colonization and succession to pre-disturbance levels. Invasive species may gain a foothold... more
Abstract Seagrass meadows evolved in the presence of disturbances and have a wide variance in recovery rate that largely follow a trajectory of re-colonization and succession to pre-disturbance levels. Invasive species may gain a foothold within native seagrass beds after space is opened by disturbances that reduce seagrass cover. Here we use shoot density monitoring data to describe growth of the invasive seagrass Halophila stipulacea in Caribbean bays over a 5-year period and conduct a series of experiments using a combination of mesocosm, seagrass removal plots, and field measurements to quantify vegetative fragment survivorship and recovery after benthic disturbance. Shoot density increased rapidly in invaded bays, reaching average densities of approximately 600 shoots/m2 within 5 years of establishment. Seagrass cover was estimated to recover to pre-disturbance level 17–31 weeks after removal from vegetative propagation of neighboring plants outside the treatment plot. Mesocosm experiments found floating and settled fragments as small as 2 cm in length and containing at least one vertical shoot survived the 4-day trial and increased in both length and biomass. Empirical evidence here demonstrates that H. stipulacea is highly resilient to small-scale disturbance which we suggest is having a transformative impact on Caribbean seagrass communities.
Research Interests:
Research Interests:
Global trade negotiations require a stringent line of certifications on accurate labeling and species traceability. National trade policies should therefore, comply with these requirements, not only to increase international... more
Global trade negotiations require a stringent line of certifications on accurate labeling and species traceability. National trade policies should therefore, comply with these requirements, not only to increase international competitiveness, but also to ensure food security, sustainability and safety. However, this is difficult to achieve without a strong basis for monitoring strategies and enforcement. In this study, issues on the identities of several species of sardines, cream dories, fish sold as fillets and choice cuts and shrimps were presented using DNA barcodes. Indications of mislabeling were found in frozen “tawilis” samples and “bluefin” tuna fillets. Some products have been identified at the species level. Finally, fish labeled as gindara steaks have been found to be a fish species which can cause health problems. These results highlight the importance of increasing national concern and government effort in food traceability and that DNA barcoding provides a robust metho...
Research Interests:
Research Interests:
Los ambientes béntico-marinos de Dominica, Antillas Menores, incluyen 1 814.7ha y cerca del 90% de la costa. Este es el primer trabajo sobre el tamaño y distribución de los ambientes costeros sublitorales y sus comunidades epibénticas.... more
Los ambientes béntico-marinos de Dominica, Antillas Menores, incluyen 1 814.7ha y cerca del 90% de la costa. Este es el primer trabajo sobre el tamaño y distribución de los ambientes costeros sublitorales y sus comunidades epibénticas. Los pastos marinos constituyeron el ambiente más extenso, con 265ha. Los arrecifes coralinos presentaron una cobertura de 72.2ha. Ambos tipos de ambientes se encontraron principalmente en la costa oeste y norte, regiones con la mayor diversidad de ambientes marinos. Las áreas rocosas (911.5ha) dominaron las costas este y sur de la isla, y junto con las áreas arenosas (566ha) constituyeron el 81% de los ambientes bénticos. La distribución de pastos marinos, que incluyeron cuatro especies nativas y una invasiva, no se pudo corroborar con los pocos informes previos. La cobertura béntica de los arrecifes coralinos de Dominica fue mucho menor que las 7 000ha que se habían reportado previamente. Estas discrepancias ilustran la ventaja de los estudios ambien...
Research Interests:
A mini-case study that uses real-world data to explore the competitive interaction among seagrasses.
This mini-case study guides students through multiple lines of evidence that suggests the most likely sister species to the lake species Sardinella tawilis, the sister species being the marine fish Sardinella hualiensis.
The dioecious seagrass species Halophila stipulacea reproduces mainly through fast clonal growth, underlying its invasive behavior. Here, we provide morphological evidence to show that the first findings of fruits in the Caribbean were... more
The dioecious seagrass species Halophila stipulacea reproduces mainly through fast clonal growth, underlying its invasive behavior. Here, we provide morphological evidence to show that the first findings of fruits in the Caribbean were misidentified. Consequently, H. stipulacea reproduction is likely still only asexual in the Caribbean. Therefore, we introduce an identification key of H. stipulacea reproductive structures to encourage careful identification and quantification throughout its invasive range. Until large-scale seed production in invaded habitats is reported, the apparent low rate of sexual reproduction needs to be considered in current studies investigating the invasion capacity of this species.
Research Interests:
Research Interests:
Seagrass beds are the largest organism-built marine habitat in Dominica, yet have only been surveyed since 2007. Standardized examinations along a depth gradient between 0 and 24 m, focusing on magnoliophyte species composition and... more
Seagrass beds are the largest organism-built marine habitat in Dominica, yet have only been surveyed since 2007. Standardized examinations along a depth gradient between 0 and 24 m, focusing on magnoliophyte species composition and benthic cover of shoots at 17 seagrass bed sites, were carried out between September 10 and December 7, 2008. The Cymodoceaceae Syringodium filiforme (Kuetzing 1860) and Halodule wrightii (Ascherson 1868), as well as the Hydrocharitaceae Halophila decipiens (Ostenfeld 1902), H. stipulacea (Fosskal & Ascherson 1867) and Thalassia testudinum (Banks ex König 1805) displayed distinct regional and horizontal distribution patterns. Syringodium filiforme is the island's dominant seagrass along the western and northern coasts, occurring at depths between 2 and 18 m and with a mean benthic cover ranging from 0.9-10% along the West coast. Along the North coast it grew between 0.2 and 1 m depth with a mean maximum benthic cover of 48.9%. Halodule wrightii grew a...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
The evolution of networks is constrained by spatial properties of the environment; a characterization that is true in both biological and built networks. Hence built networks such as urban streets can be compared to biological networks to... more
The evolution of networks is constrained by spatial properties of the environment; a characterization that is true in both biological and built networks. Hence built networks such as urban streets can be compared to biological networks to reveal differences in efficiency and complexity. This study assessed foraging networks created by the slime-mold Physarium polycephalum on proportional 3D-printed topographic maps of metropolitan city of Los Angeles, California. Rapidly-generated isomorphic solutions were found to be consistently and statistically shorter than existing roadways in system length. Slime mold also allocated resources to supporting key nodes, analogous to how heavy traffic flows through major intersections. Further, chemical deterrents inhibited exploration of slime mold in selected areas and allows for testing of network redundancy and system resilience, such as after an earthquake or wildfire.
Research Interests:
Longtail tuna (Thunnus tonggol) is a neritic species that supports commercial, artisanal and recreational fisheries throughout the Indo-Pacific region. Historically receiving little attention by commercial fisheries, the global annual... more
Longtail tuna (Thunnus tonggol) is a neritic species that supports commercial, artisanal and recreational fisheries throughout the Indo-Pacific region. Historically receiving little attention by commercial fisheries, the global annual catch of longtail tuna has steadily risen from around 30,000 t in the early 1980s to exceeding 200,000 t since 2004, reaching a peak of 291,264 t in 2007, and was 281,613 t in 2017. Catches of longtail tuna in the Indian Ocean now exceed catches of principal commercial target species, such as albacore and bigeye tunas. A sequence of stock assessments undertaken throughout the species’ range since the late 1980s persistently indicated that at least three of the four stocks defined in this paper are likely to have been, and most likely are currently, subject to overfishing and overfished as a result of excess fishing effort on this relatively slow-growing and long-lived tuna species. As the spawning biomass of principal tuna target species continue to decline in both the Indian and western and central Pacific Oceans, the increasing catches of longtail tuna, other neritic tunas, and seerfishes is worrisome. Few conservation and management measures (CMMs) are currently in place specifically for longtail tuna, although in recent years some coastal States, Regional Fishery Bodies, and tuna Regional Fisheries Management Organisations have begun to develop initiatives to improve the catch and biological data quality for longtail tuna and sympatric species of neritic tunas and tuna-like species. This paper provides a global review of biological, ecological and fishery information to provide researchers, fishery managers and policy makers with the most current information from which to begin to guide future stock assessment and the development of CMMs for longtail tuna.
Research Interests:
Research Interests:
While the seagrass Halophila stipulacea reproduces both sexually and asexually in its native range, reproduction is largely asexual in its invasive range in the Mediterranean and the Caribbean Seas. Here we make the first report of... more
While the seagrass Halophila stipulacea reproduces both sexually and asexually in its native range, reproduction is largely asexual in its invasive range in the Mediterranean and the Caribbean Seas. Here we make the first report of fruit-bearing H. stipulacea in the Caribbean. Although the lack of reports of H. stipulacea fruit could be the consequence of past survey effort, multiple recent reports of both flowers and fruit across the invasive range strongly suggest that introductions of H. stipulacea in the tropical western Atlantic and Caribbean included both sexes of this dioecious seagrass. This finding may have important implications for the future dispersal, survival, and maintenance of the non-native population.
Research Interests:
Research Interests:
The United States is the world's largest fish importer. Recent reports, however, indicate that 25-30% of wild-caught seafood imported into the US is illegally caught, heightening concerns over the country's significant role in... more
The United States is the world's largest fish importer. Recent reports, however, indicate that 25-30% of wild-caught seafood imported into the US is illegally caught, heightening concerns over the country's significant role in driving Illegal, Unreported, and Unregulated (IUU) fishing. In January 2017, NOAA enacted the Seafood Import Monitoring Program in an effort to combat IUU fishing through mandating improved seafood traceability requirements. This program requires reporting of fisheries data from harvest to arrival at the US border. Given the role of the US as a major global importer of seafood, this regulation could be a transformative action on fisheries worldwide if implementation includes two key components-(1) applying best available and most appropriate technologies and (2) building monitoring and enforcement capacity among trading nations. This paper provides insightful commentary on the potential for this US policy to lead by example and improve an essential nat...
Research Interests:
Research Interests:
Research Interests:
T he blue swimming crab, Portunus pelagicus (Brachyura, Portunidae), is a widely distributed crab species across much of the Indo-West Pacific. A recent taxonomic revision based on morphological and genetic divergence between populations... more
T he blue swimming crab, Portunus pelagicus (Brachyura, Portunidae), is a widely distributed crab species across much of the Indo-West Pacific. A recent taxonomic revision based on morphological and genetic divergence between populations across the species’ vast range has revealed that the species is actually a four-member species complex. These species, P. pelagicus sensu stricto, P. reticulatus (Herbst 1799), P. armatus (A. Milne-Edwards 1861), and P. segnis (Forskal 1775), have juxtaposed ranges with some peripheral regions of overlap. The species P. pelagicus sensu stricto is believed to be the sole representative of this species-complex occurring across the entire Philippine archipelago. Here we test this assumption using the mitochondrial Cytochrome oxidase sub-unit I gene region and identify the presence of two Portunus species, P. pelagicus sensu stricto and a previously identified but un-described Portunus