Aquaculture and Fisheries Commons^™

Extinction Risk Of Coral Reef Fishes In The Philippine Marine Ornamental Trade, Jemelyn Grace Baldisimo Sepulveda

Biological Sciences Theses & Dissertations

Coral reef ecosystems in the Philippines face severe threats from intense fishing and habitat degradation. This dissertation evaluated the extinction risk of fishes in the Philippine Marine Aquarium Trade (MAT) using Productivity Susceptibility Analysis (PSA) and temporal genomics. A global PSA framework was modified by including local susceptibility factors. Of the 103 species evaluated, six were categorized as highly vulnerable and 62 as moderately vulnerable, revealing increased local vulnerability and underscoring the importance of local assessments to guide conservation efforts.

Temporal genomics compared historical (1908–1909 U.S.S. Albatross Expedition) and contemporary populations of the MAT-targeted Sphaeramia nematoptera and Pseudanthias squamipinnis, …

Evaluating Species At Risk In Data-Limited Fisheries: A Productivity-Susceptibility Analysis For Marine Aquarium Fish, Gabrielle A. Baillargeon, Alice A. Wynn, Jemelyn Grace P. Baldisimo, Michael F. Tlusty, Andrew L. Rhyne

Biological Sciences Faculty Publications

The marine aquarium trade (MAT) is a significant global industry harvesting millions of wild-caught, live coral reef fishes for public and private aquaria markets in the United States and Europe annually, while supporting fisher livelihoods in the Indo-Pacific. This diverse and species-rich trade is considered data-limited, creating barriers to quantifying the current and future socio-ecological sustainability of the fishery. We present a revised and expanded productivity–susceptibility analysis (PSA) that serves as a holistic risk assessment to estimate the vulnerability of marine aquarium fish to overfishing. Our global analysis includes 306 species that are actively in trade. Improvements to the PSA …

Does Fishery Management For Groupers (Teleostei: Epinephelidae) Protect Them Effectively? Context From The Iucn's Red List Of Threatened Species, Sean T. Fennessy, Christi Linardich, Kevin Rhodes, Joao P. Barreiros, David Pollard, Eloy Sosa-Cordero, Felicia Coleman, Alfonso Aguilar-Perera, Christopher R. Malinowski, Thierry Brulé, Pedro Afonso, Kayan Ma, Min Liu, Muktha Menon, Colin Wen, Stanley K. H. Shea, Sean N. Porter, Matthew Craig, Yvonne Sadovy De Mitcheson

Biological Sciences Faculty Publications

Worldwide, groupers (Epinephelidae) are commercially valued fishes, which also play key ecological roles on tropical and subtropical reefs. In 2007 and 2016, the IUCN's Groupers and Wrasses Specialist Group assessed all 160+ grouper species, with 17 of these being identified as threatened in 2016 and the major threat factor being overexploitation. Our present study aimed to identify whether management measures (MMs) for previously assessed groupers were established, whether these measures aligned with IUCN's Red List categories, and whether they effectively protect grouper populations. Experts in grouper biology and management assigned scores per grouper species based on the extent to which …

Mitochondrial Genome Of The Indo-Pacific Mesophotic Coral Leptoseris Columna (Scleractinia: Agariciidae) Assembled Using Pacbio Long-Read Sequencing, Nomita Rani Adhikary, Daniel J. Barshis, J. Antonio Baeza

Biological Sciences Faculty Publications

Leptoseris columna, a mesophotic coral species belonging to the family Agariciidae, is distributed throughout the Indo-Pacific region. This species is considered as of "Least concern" by the IUCN, yet, faces multiple local and global stressors. To support conservation plans, this study sequenced and characterized the complete mitochondrial genome of L. columna. The complete mitochondrial genome of Leptoseris columna was assembled using PacBio long-reads with a coverage of 459× per bp. The AT-rich mitochondrial genome of Leptoseris columna is 18,546 bp long and comprises 13 protein-coding genes (PCGs), 2 transfer RNA genes (trnM and trnW), and 2 ribosomal RNA …

Larval Genomics As A Viable, Fisheries-Independent Tool For Investigating Population Structure In Tropical Pacific Tunas, Jacob E. Jaskiel, Hannah E. Aichelman, Giulia Anderson, Louw Claassens, James E. Fifer, Christina M. Hernandez, Alexa K. Huzar, Joel K. Llopiz, Jan W. Witting, Sean P. Mullen, Randi D. Rotjan

Biological Sciences Faculty Publications

Understanding how dispersal, life history, and environmental variability shape genetic connectivity in the open ocean remains a central challenge in evolutionary biology. Highly migratory marine predators like tunas have traditionally been considered genetically homogeneous across ocean basins, yet emerging genomic evidence suggests that cryptic population structure can persist even in species with high gene flow and large effective population sizes. We used 2bRAD sequencing of 348 larval and subadult skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares), and bigeye tuna (T. obesus) collected from the central Pacific across 7 years of sampling to examine species boundaries, …

A Re-Evaluation Of Atlantic Bluefin Tuna (Thunnus Thynnus) Spawning Distribution In The Western Atlantic Ocean, David E. Richardson, Katrin E. Marancik, Malgorzata Adamus, Elizabeth A. Broughton, Robert K. Cowen, Trika Gerard, Christina M. Hernández, John J. Hoey, Joel K. Llopiz, Molly E. Lutcavage, Estrella Malca, Debra L. Palka, Lourdes Vásquez-Yeomans, Harvey J. Walsh, C. Michelle Willis, Glenn A. Zapfe

Biological Sciences Faculty Publications

There is currently a lack of consensus on the spatial, seasonal and decadal-scale patterns of Atlantic bluefin tuna (Thunnus thynnus) spawning in the western Atlantic Ocean. We compiled ichthyoplankton and reproductive data to characterize bluefin spawning patterns and the uncertainty in these patterns. Ichthyoplankton data indicates that bluefin spawn in the Gulf of America/Gulf of Mexico, northwest Caribbean Sea, north of the Bahamas, along the inshore edge of the Florida Current off the Carolinas and in the western Slope Sea. Reproductive studies identified these same spawning areas, as well as the Windward Passage and waters east of the …

Impacts Of Offshore Wind Energy Development On The Commercial Sea Scallop Fishery, Sarah Borsetti, Daphne M. Munroe, John M. Klinck, Andrew M. Scheld, Eileen E. Hofmann, Eric N. Powell, David B. Rudders

CCPO Publications

The Atlantic sea scallop (Placopecten magellanicus) fishery on the Northeast U.S. continental shelf generates approximately USD 500 million ex-vessel revenues annually, making it one of the most valuable single species fisheries in the United States. Wind energy development is planned for key areas on the U.S. Mid-Atlantic shelf where the Atlantic sea scallop fishery operates, creating novel challenges in managing trade-offs between traditional users like fisheries and new users like offshore wind energy. An agent-based modeling framework that integrates spatial dynamics in Atlantic sea scallop stock biology, fishing fleet behavior, and federal management decisions, was implemented to investigate …

Evaluating The Chemical Reactivity Of Wildfire-Derived Dissolved Organic Molecules: Glutathione Binding Through Kendrick Mass Defect Analysis, Hannah M. Hamontree, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

The emerging risks to organisms of pyrogenic-derived dissolved organic matter (PyDOM) from forest fires are of concern due to its toxic and mutagenic potential (e.g., pro-oxidative responses in fauna through the depletion of glutathione, a nitrogen- and sulfur-containing tripeptide found in cells). This study simulates this phenomenon in a laboratory setting by identifying bonding between reduced l-glutathione and organic molecules in leachates from environmentally weathered biomass samples (charred and uncharred) using Kendrick Mass Defect (KMD) analysis from formula lists obtained from negative-mode electrospray ionization-Fourier transform-ion cyclotron resonance-mass spectrometry ((-)ESI-FT-ICR-MS). These formula lists reveal a 10-fold increase in nitrogen- and sulfur-containing …

Low Salinities Impair Heat Tolerance And Alter Reproductive Traits With No Implications For Survival In A Marine Annelid From Coastal Habitats, Gabrielle Newton, Gloria Massamba-N'Siala

Biological Sciences Faculty Publications

Climate change is expected to intensify salinity and temperature fluctuations in estuarine and coastal habitats. However, the impact of salinity variation on ectotherms’ thermal tolerance remains underexplored, limiting our understanding of the interplay between these stressors. This study investigated salinity-dependent changes in life history traits (survival, growth rate, fecundity, and egg size) over a 33-day exposure to a salinity gradient (12, 17, 22, 27, 32, 35, 40, 45, 50) in the marine annelid Ophryotrocha labronica. Individuals that survived the salinity treatments were assessed for their upper and lower thermal tolerance limits. Female individuals, the target of the study, exhibited …

Cellular Responses Of Astrangia Poculata (Ellis And Solander, 1786) And Its Symbiont To Experimental Heat Stress, Tyler E. Harman, Daniel Barshis, Briana Hauff Salas, Kevin B. Strychar

Biological Sciences Faculty Publications

Climate change has had devastating effects on tropical coral reefs; however, much less is known regarding how heat stress affects temperate coral. This research focuses on Astrangia poculata (Ellis and Solander, 1786) collected from Narragansett Bay, RI, during the summer and winter seasons and understanding the effect of experimental thermal extremes (i.e., 26 °C) on seasonally different populations. Photosynthetic efficiency (Fv/Fm), symbiont density (via an inverse relationship with pixel intensity), and oxidative stress via reactive oxygen species (ROS) concentrations were measured on symbiotic and aposymbiotic A. poculata. Higher Fv/Fm rates were observed in summer- vs. winter-collected corals (p ≤ …

A Multispecies, Multisite Assessment Of Coral Thermal Tolerances In American Samoa, Using Acute Heat Stress Assays, Ponchanok Weeriyanun, Nicolas R. Evensen, Katherine E. Parker, Veronica Z. Radice, Daniel J. Barshis

Biological Sciences Faculty Publications

Reef-building corals are being impacted by increasing seawater temperatures, with marine heatwaves leading to mass bleaching events and extensive mortality. However, corals can display variation in thermal tolerance, both within and among species. In this study, we sampled four coral species (Acropora hyacinthus, Montipora grisea, Pocillopora verrucosa, and Porites lobata) from two sites on Tutuila, American Samoa, with contrasting environmental regimes but similar Maximum Monthly Means (MMM). Coral fragments were subjected to short-term acute heat stress experiments using the Coral Bleaching Automated Stress System (CBASS). PAM Fluorometry was used to measure the symbiont’s effective quantum yield (Fv/Fm) following heat stress …

Assemblage Structure Of Large Carnivorous Coral Reef Fishes At Shallow And Mesophotic Depths In Two Of The Largest And Most Isolated Marine Protected Areas In The Philippines, Rene A. Abesamis, Mikaela L. Salvador, Ryan Murray, Kymry Delijero, Segundo F. Conales, Jean T. Utzurrum, Christopher E. Bird, David T. Gauthier

Biological Sciences Faculty Publications

Overfishing remains a threat to coral reef fishes globally, with large carnivores often the most vulnerable. Marine protected areas (MPAs) can restore fish populations and biodiversity, but their impact has been understudied in mesophotic coral ecosystems (MCEs – extensions of shallow reefs from 30 to 150 m). We analyzed baited remote underwater videos recorded in 2016 to investigate the assemblage structure of large carnivorous fishes at shallow (4–12 m) and mesophotic (45–96 m) depths in two of the largest and most isolated MPAs in the Philippines: Tubbataha Reefs Natural Park (TRNP), a fully no-take MPA enacted in 1988; and Cagayancillo, …

Addressing The Productivity-Susceptibility Analysis In Data-Limited Fisheries For Understudied Fish In The Marine Aquarium Trade, Alice Wynn, Jemelyn Baldisimo, Gabrielle Baillargeon, Michael Tlusty, Andrew Rhyne

Biological Sciences Faculty Publications

The marine aquarium trade (MAT) harvests millions of coral reef fishes from the wild yearly. While the MAT supports fishers, hobbyists and marine education, harvested fishes are crucial in maintaining coral reef health and balanced marine cycles within their native habitats. Understanding the impact of the MAT on fish populations is critical for sustaining the trade in the long-term. Productivity-susceptibility analyses (PSAs) offer semiquantitative methods of analyzing the productive capacity of each fish stock, as well as its susceptibility to overfishing. The present study revises and expands upon a PSA conducted by Baillargeon et al. (2020) that focused on 32 …

Squid Paralarvae Turn With High Agility Using Jets Near The Reynolds Number Threshold For Viscous Domination, Ian K. Bartol, Alissa M. Ganley, Paul S. Krueger, Joseph T. Thompson

Biological Sciences Faculty Publications

Turning is critical for survival in the ocean, as marine animals need to maneuver to capture prey, elude predators, and navigate complex environments. While prior research has focused on turning performance of adult swimmers, less is known about early ontogenetic stages that locomote within lower Reynolds number (Re) regimes, especially young jetters. To evaluate squid paralarval turning proficiency and the role of the pulsed jet in maneuvers, recently hatched longfin squid Doryteuthis pealeii swimming in a viewing chamber were studied using digital particle image velocimetry and kinematic motion analyses. Paralarvae exhibited a wide repertoire of turning behaviors, including those performed …

Genome-Wide Snp Analyses Reveal High Gene Flow Of Endemic Smallscale Croaker (Boesemania Microlepsis) In The Lower Mekong Basin, Quyen Dang Ha Vu, Christopher E. Bird, Oanh Thi Truong, Sang Quang Tran, Ellen E. Biesack, Amanda S. Ackiss, Kent E. Carpenter, Binh Truy Dang

Biological Sciences Faculty Publications

The Smallscale Croaker, Boesemania microlepis, is a valuable fishery resource in the Mekong River basin that lacks clear biological data to understand its basic ecology and conservation management priorities. This species is common in the southernmost floodplain of the Mekong which extends from Tonlé Sap in Cambodia to the Mekong Delta in Vietnam. This floodplain is of particular biodiversity conservation concern because of the many upstream dams that restrict water flow in an ecology that relies heavily on a flood-pulse cycle. The literature regarding the biology B. microlepis in this region contains conflicting ideas that populations are both highly …

Successful Eastern Oyster (Crassostrea Virginica) Recruitment On Intertidal Artificial Substrates In Virginia, Usa, Rochelle D. Seitz, Kathleen E. Knick, Emily Suchonic, Amanda Pysher

OES Faculty Publications

Declines of eastern oyster (Crassostrea virginica) populations and scarcity of natural oyster shell necessitate quantifying the effectiveness of artificial oyster reef substrates over varying environmental conditions. Oyster castles are often used in intertidal areas with moderate wave energy; however, new concrete, natural-looking substrates, GROW Reef Tiles, are now available. Eastern oyster recruitment and size on oyster castles (OC) and GROW Reef Tiles (GT), with 27% higher surface area on OC, were assessed three times over 25 months in locations with varying salinity. Four sites in the Chesapeake Bay region were examined: Cherrystone Inlet, Mockhorn Bay, Elizabeth River, and …

Time Series Modeling To Ascertain Age In Fisheries Management, Kathleen Sue Kirch

OES Theses and Dissertations

The ability to assign accurate ages of fish is important to fisheries management. Accurate ageing allows for the most reliable age-based models to be used to support sustainability and maximize economic benefit. Structures used to age include bones, scales, and most commonly ear bones (otoliths). Assigning age relies on validating putative annual marks by evaluating accretional material laid down in patterns in fish otoliths, typically by marginal increment analysis. These patterns often take the shape of a sawtooth wave with an abrupt drop in accretion yearly to form an annual band and are typically validated qualitatively. Researchers have shown keen …

Baby's First Jets: A Kinematic And Hydrodynamic Analysis Of Turning In Cuttlefish Hatchlings, Alissa M. Ganley, Paul S. Krueger, Ian K. Bartol

Biological Sciences Faculty Publications

Turning is an important aspect of life underwater, playing integral roles in predator avoidance, prey capture, and communication. While turning abilities have been explored in a diversity of adult nekton, little is currently known about turning in early ontogeny, especially for cephalopods. In this study, we investigated the turning abilities of hatchling common cuttlefish (Sepia officinalis, n = 49) and dwarf cuttlefish (Sepia bandensis, n = 30), using both kinematic and wake-based analyses. Using body tracking software and particle image velocimetry (PIV), we found that S. officinalis turned faster than S. bandensis, but both species …

Western Boundary Current-Subtropical Continental Shelf Interactions, William B. Savidge, Dana K. Savidge, Frederico Brandini, Adam T. Greer, Eileen E. Hofmann, Moninya Roughan, Iison De Silvera, Iain M. Suthers

CCPO Publications

Western boundary currents (WBCs) adjacent to subtropical continental shelves (STCSs; between ~25° and 35° latitude; Figure 1) transport heat, nutrients, and biota poleward along the western margins of major ocean basins, interacting with the continental margins and influencing their physics and biology. Eddies and meanders along the shelf edge upwell deep, nutrient-laden water that can be advected onto the adjacent shelves with a corresponding export of particle-rich shelf water (e.g., Lee et al., 1991; Kimura et al., 1997; Campos et al., 2000; Roughan and Middleton, 2002, 2004; Lutjeharms, 2006; Savidge and Savidge, 2014). Despite their similarities, the various STCS regions …

Abalones At Risk: A Global Red List Assessment Of Haliotis In A Changing Climate, Howard Peters, Gina M. Ralph, Laura Rogers-Bennett

Biological Sciences Faculty Publications

There is increasing awareness that marine invertebrates such as abalones are at risk from the combined stressors of fishing and climate change. Abalones are an important marine fishery resource and of cultural importance to Indigenous and non-Indigenous people. A highly priced marine delicacy, they are inherently vulnerable: individuals are slow-growing and long-lived and successful reproduction requires dense assemblages. However, their global conservation status is poorly understood. Using IUCN Red List methodology, we assessed the extinction risk to all 54 species of abalone (genus Haliotis). Of the 21 fished commercially for human consumption either now and/or in the past, 15 …

Complex Dynamics Of Coral Gene Expression Responses To Low Ph Across Species, Veronica Z. Radice, Ana Martinez, Adina Paytan, Donald C. Potts, Daniel J. Barshis

Biological Sciences Faculty Publications

Coral capacity to tolerate low pH affects coral community composition and, ultimately, reef ecosystem function. Low pH submarine discharges (‘Ojo’; Yucatán, México) represent a natural laboratory to study plasticity and acclimatization to low pH in relation to ocean acidification. A previous >2‐year coral transplant experiment to ambient and low pH common garden sites revealed differential survivorship across species and sites, providing a framework to compare mechanistic responses to differential pH exposures. Here, we examined gene expression responses of transplants of three species of reef‐building corals (Porites astreoides, Porites porites and Siderastrea siderea) and their algal endosymbiont communities …

The Impacts Of Anthropogenic Activity And Climate Change On The Formation Of Harmful Algal Blooms (Habs) And Its Ecological Consequence, Zhangxi Hu, Aifeng Li, Zhun Li, Margaret R. Mulholland

OES Faculty Publications

No abstract provided.

Diel Vertical Migration Rates Of The Dinoflagellate Species Margalefidinium Polykrikoides In A Lower Chesapeake Bay Tributary, S. Clayton, Jacqueline B. Chrabot, Michael Echevarria, Leah Gibala-Smith, Kathryn Mogatas, Peter Bernhardt, Margaret R. Mulholland

OES Faculty Publications

Margalefidinium polykrikoides is a mixotrophic dinoflagellate harmful algal bloom (HAB) species that blooms annually in the lower Chesapeake Bay. M. polykrikoides undertakes a diel vertical migration (DVM) which may give it a competitive advantage over purely phototrophic organisms who cannot access deeper nutrient pools and allow it to form large toxic blooms. Laboratory-based estimates of M. polykrikoides’ DVM rates suggest that it is one of the fastest known dinoflagellate swimmers and understanding this behavior is likely important for modeling and predicting M. polykrikoides blooms. However, to date, no field-derived estimates of M. polykrikoides’ DVM rates have been made in the …

Biodiversity Of Philippine Marine Fishes: A Dna Barcode Reference Library Based On Voucher Specimens, Katherine E. Bemis, Matthew G. Girard, Mudjekeewis D. Santos, Kent E. Carpenter, Jonathan R. Deeds, Diane E. Pitassy, Nicko Amor L. Flores, Elizabeth S. Hunter, Amy C. Driskell, Kenneth S. Macdonald Iii, Lee A. Weigt, Jeffrey T. Williams

Biological Sciences Faculty Publications

Accurate identification of fishes is essential for understanding their biology and to ensure food safety for consumers. DNA barcoding is an important tool because it can verify identifications of both whole and processed fishes that have had key morphological characters removed (e.g., filets, fish meal); however, DNA reference libraries are incomplete, and public repositories for sequence data contain incorrectly identified sequences. During a nine-year sampling program in the Philippines, a global biodiversity hotspot for marine fishes, we developed a verified reference library of cytochrome c oxidase subunit I (COI) sequences for 2,525 specimens representing 984 species. Specimens were primarily purchased …

Quantifying Antarctic Krill Connectivity Across The West Antarctic Peninsula And Its Role In Large-Scale Pygoscelis Penguin Population Dynamics, Katherine L. Gallagher, Michael S. Dinniman, Heather J. Lynch

CCPO Publications

Antarctic krill (Euphausia superba) are considered a keystone species for higher trophic level predators along the West Antarctic Peninsula (WAP) during the austral summer. The connectivity of krill may play a critical role in predator biogeography, especially for central-place foragers such as the Pygoscelis spp. penguins that breed along the WAP during the austral summer. Antarctic krill are also heavily fished commercially; therefore, understanding population connectivity of krill is critical to effective management. Here, we used a physical ocean model to examine adult krill connectivity in this region using simulated krill with realistic diel vertical migration behaviors across …

Potential Repercussions Of Offshore Wind Energy Development In The Northeast United States For The Atlantic Surfclam Survey And Population Assessment, Sarah Borsetti, Daphne M. Munroe, Andrew M. Scheld, Eric N. Powell, John M. Klinck, Eileen E. Hofmann

CCPO Publications

The Atlantic surfclam Spisula solidissima fishery, which spans the U.S. Northeast continental shelf, is among the most exposed to offshore wind energy development impacts because of the overlap of fishing grounds with wind energy lease areas, the hydraulic dredges used by the fishing vessels, and the location of vessel home ports relative to the fishing grounds. The Atlantic surfclam federal assessment survey is conducted using a commercial fishing vessel in locations that overlap with the offshore wind energy development. Once wind energy turbines, cables, and scour protection are installed, survey operations within wind energy lease areas may be curtailed or …

Integrating Human Dimensions In Decadal-Scale Prediction For Marine Social Ecological Systems: Lighting The Grey Zone, Jess Melbourne-Thomas, Desiree Tommasi, Marion Gehlen, Eugene J. Murphy, Jennifer Beckensteiner, Francisco Bravo, Tyler D. Eddy, Mibu Fischer, Elizabeth Fulton, Mayya Gogina, Eileen Hofmann, Maya Ito, Sara Mynott, Kelly Ortega-Cisneros, Anna N. Osiecka, Mark R. Payne, Romeo Saldívar-Lucio, Kim J.N. Scherrer

CCPO Publications

The dynamics of marine systems at decadal scales are notoriously hard to predict-hence references to this timescale as the "grey zone" for ocean prediction. Nevertheless, decadal-scale prediction is a rapidly developing field with an increasing number of applications to help guide ocean stewardship and sustainable use of marine environments. Such predictions can provide industry and managers with information more suited to support planning and management over strategic timeframes, as compared to seasonal forecasts or long-term (century-scale) predictions. The most significant advances in capability for decadal-scale prediction over recent years have been for ocean physics and biogeochemistry, with some notable advances …

Interactive Effects Of Climate Change-Induced Range Shifts And Wind Energy Development On Future Economic Conditions Of The Atlantic Surfclam Fishery, Stephanie Stromp, Andrew M. Scheld, John M. Klinck, Daphne M. Munroe, Eric N. Powell, Roger Mann, Sarah Borsetti, Eileen E. Hofmann

CCPO Publications

Rising water temperatures along the northeastern U.S. continental shelf have resulted in an offshore range shift of the Atlantic surfclam Spisula solidissima to waters still occupied by ocean quahogs Arctica islandica. Fishers presently are prohibited from landing both Atlantic surfclams and ocean quahogs in the same catch, thus limiting fishing to locations where the target species can be sorted on deck. Wind energy development on and around the fishing grounds will further restrict the fishery. A spatially explicit model of the Atlantic surfclam fishery (Spatially Explicit Fishery Economics Simulator) has the ability to simulate the consequences of fishery displacement …

A Growth Model For Arctica Islandica: The Performance Of Tanaka And The Temptation Of Von Bertalanffy—Can The Two Coexist?, John M. Klinck, Eric N. Powell, Kathleen M. Hemeon, Jillian R. Sower, Daniel R. Hennen

CCPO Publications

Organisms increase in size over time (age) due to excess assimilation over metabolic (respiration) energy demands. Most organisms reach a maximum size with increasing age as gain and loss balance. The von Bertalanffy length-at-age relationship, which is commonly used in fishery assessment calculations, imposes such a maximum size. However, some fished species, such as ocean quahogs, Arctica islandica, are long lived and continue to grow at old age. The Tanaka age-at-length relationship has continued growth at old age, but is rarely used in stock assessment models. A modified form of the von Bertalanffy model is presented, which mimics the …

The Southern Ocean Ecosystem Affects The Entire World, Eugene J. Murphy, Nadine M. Johnston, Eileen E. Hofmann, Richard A. Phillips, Jennifer E. Jackson, Andrew J. Constable

CCPO Publications

The Southern Ocean, which flows around the Antarctic continent, is home to vast numbers of unique and remarkable animals, including penguins, albatrosses, petrels, seals, and whales. The ocean bursts into life every spring, fueling a summer feeding and breeding frenzy. During the dark winter months, there is little food and life is very harsh. Human activities such as fishing and pollution are affecting this ecosystem, as is climate change. These ecosystem changes matter beyond the Southern Ocean! Ocean currents carry nutrients and organisms into and out of the Southern Ocean. Many marine mammals and seabirds swim or fly in and …