McGowan C.P.,U.S. Geological Survey |
McGowan C.P.,North Carolina State University |
Smith D.R.,U.S. Geological Survey |
Sweka J.A.,U.S. Fish and Wildlife Service |
And 8 more authors.
Natural Resource Modeling | Year: 2011
Adaptive management requires that predictive models be explicit and transparent to improve decisions by comparing management actions, directing further research and monitoring, and facilitating learning. The rufa subspecies of red knots (Calidris canutus rufa), which has recently exhibited steep population declines, relies on horseshoe crab (Limulus polyphemus) eggs as their primary food source during stopover in Delaware Bay during spring migration. We present a model with two different parameterizations for use in the adaptive management of horseshoe crab harvests in the Delaware Bay that links red knot mass gain, annual survival, and fecundity to horseshoe crab dynamics. The models reflect prevailing hypotheses regarding ecological links between these two species. When reported crab harvest from 1998 to 2008 was applied, projections corresponded to the observed red knot population abundances depending on strengths of the demographic relationship between these species. We compared different simulated horseshoe crab harvest strategies to evaluate whether, given this model, horseshoe crab harvest management can affect red knot conservation and found that restricting harvest can benefit red knot populations. Our model is the first to explicitly and quantitatively link these two species and will be used within an adaptive management framework to manage the Delaware Bay system and learn more about the specific nature of the linkage between the two species. © 2011 Wiley Periodicals, Inc.
News Article | February 28, 2017
A new analysis of population trends among coastal sharks of the southeast U.S. shows that all but one of the seven species studied are increasing in abundance. The gains follow enactment of fishing regulations in the early 1990s after decades of declining shark numbers. Scientists estimate that over-fishing of sharks along the southeast U.S. coast--which began in earnest following the release of Jaws in 1975 and continued through the 1980s--had reduced populations by 60-99% compared to un-fished levels. In response, NOAA's National Marine Fishery Service in 1993 enacted a management plan for shark fisheries that limited both commercial and recreational landings. Now, says lead scientist Cassidy Peterson, a graduate student at William & Mary's Virginia Institute of Marine Science, "We've shown that after over two decades of management measures, coastal shark populations are finally starting to recover and reclaim their position as top predators, or regulators of their ecosystem. Our research suggests we can begin to shift away from the era of 'doom and gloom' regarding shark status in the United States." Joining Peterson in the study, published in the latest issue of Fish and Fisheries, were VIMS professor Rob Latour, Carolyn Belcher of the Georgia Department of Natural Resources, Dana Bethea and William Driggers III of NOAA's Southeast Fisheries Science Center, and Bryan Frazier of the South Carolina Department of Natural Resources. The researchers say their study--based on modeling of combined data from six different scientific surveys conducted along the US East Coast and in the Gulf of Mexico between 1975 and 2014--provides a more accurate and optimistic outlook than previous studies based on commercial fishery landings or surveys in a single location. "Data from shark long-lining operations or shark bycatch can be suspect," says Peterson, "because what looks like a change in abundance might instead be due to changes in fishing gear, target species, market forces, or other factors." Research surveys are scientifically designed to remove these biases. Survey crews purposefully sample a random grid rather than visiting known shark hot spots, and strive to use the exact same gear and methods year after year to ensure consistency in their results. But even with these safeguards, data from a single survey often aren't enough to capture population trends for an entire shark species, whose members may occupy diverse habitats and migrate to different and far-flung areas depending on age and sex. "Because many shark species undergo vast migrations and have complex life cycles," says Peterson, "it's not uncommon for results from different surveys to conflict. Producing an estimate of total abundance requires combining data from different surveys--sometimes from several states or even countries--and applying intricate stock-assessment models." For the current study, the scientists combined data from six different shark surveys: the VIMS Longline Survey, the SouthEast Area Monitoring and Assessment Program's South Atlantic Coastal Trawl Survey, the South Carolina Coastal Longline Survey, the Georgia Red Drum Longline Survey, the Southeast Fisheries Science Center's Longline Survey, and the Gulf of Mexico Shark Pupping and Nursery Area Gillnet Survey. "Our study represents the most comprehensive analysis of patterns in abundance ever conducted for shark species common to our area and the Southeast coast," says Latour, who directs the longline survey at VIMS. Established in 1973, it is the world's longest running fishery independent monitoring program for sharks, skates, and rays. By pooling and modeling data from all six surveys, the researchers were able to estimate population trends for seven of the region's most common coastal species: the large-bodied sandbar, blacktip, spinner, and tiger sharks, and the smaller Atlantic sharpnose, blacknose, and bonnethead sharks. The results of the analysis were clear, says Peterson. "All the large-bodied sharks showed similar population trends, with decreasing abundance from the mid-1970s to the early 1990s, then a multi-year period of low abundance, and recent indications of recovery from past exploitation." All but one population of small coastal sharks also increased in abundance. The exception was blacknose sharks in the Gulf of Mexico, which decreased from the onset of records in 1989 until the study's end in 2014. This species is known to be susceptible to by-catch within the trawl fishery for Gulf shrimp. The blacknose population along the Atlantic coast of the southeast U.S. actually increased during the same period. The overall population trends make biological sense, says Latour. "The large-bodied species saw the greatest initial declines, both because they were highly sought by anglers, and because they mature late and produce relatively few pups. Their slow growth rate also helps explain the pause in their recovery following the onset of fishing regulations in the early 1990s." The smaller shark species, whose higher growth rates make them less susceptible to fishing pressure, saw lesser declines and more rapid recoveries. The team also found a correlation between shark numbers and both fishing pressure and large-scale climatic patterns. Funding for the study was provided by NOAA Fisheries, the NMFS Highly Migratory Species Office, the Atlantic States Marine Fisheries Commission, the South Carolina Saltwater Recreational Fishing License Funds, and the Federal Assistance for Interjurisdictional Fisheries Program.
Havel L.N.,University of Texas at Austin |
Havel L.N.,Atlantic States Marine Fisheries Commission |
Fuiman L.A.,University of Texas at Austin |
Ojanguren A.F.,University of Texas at Austin |
Ojanguren A.F.,University of St. Andrews
Aquatic Biology | Year: 2015
Settlement is the last stage of high mortality in the life cycle of demersal marine fishes, making the number of larvae that successfully settle to a benthic habitat a predictor of future population size. Habitat selection is an active settlement process for coral reef fishes, however, there has been less research about settlement in other ecosystems. This study used laboratory and field experiments to examine the relationship between size and settlement over various substrates in red drum Sciaenops ocellatus, a temperate and subtropical estuarine species. In the laboratory, vertical position of fish (4.3 to 40.0 mm standard length [SL]) was recorded in the presence of sand, oyster shells, or seagrass to determine median settlement size. Median settlement size was 12.9 mm SL for seagrass, 15.8 mm SL for sand, and 20.5 mm SL for oyster shells. To determine the size at which fish settle in the wild, vertically partitioned field enclosures were used to separate individuals (5.2 to 37.3 mm SL) in the water column (>16 cm from the sediment) from those in the seagrass (<16 cm from the sediment). Larvae in the water column were smaller than in the seagrass (9.3 vs. 14.3 mm SL). Previous studies reported that red drum reach nursery habitats at 4 mm SL, but this study suggests that they do not use structured habitats at first. Instead, this fish settles at different sizes to various habitats, which can be interpreted as evidence for active settlement. © The authors 2015.
Havel L.N.,University of Texas at Austin |
Havel L.N.,Atlantic States Marine Fisheries Commission |
Fuiman L.A.,University of Texas at Austin
Estuaries and Coasts | Year: 2016
Planktonic larvae combine directed swimming and functional sensory systems to locate benthic habitats. Some adult marine fishes use chemical cues for orientation to specific habitats, but olfactory function for estuarine fish larvae has received little research attention. This laboratory study quantified behavioral responses of red drum (Sciaenops ocellatus) larvae to estuarine chemical cues to examine the role of water chemistry as an orientation cue for locating or remaining in settlement habitat. Spontaneous activity (kinesis) was measured for pre-settlement-size larvae exposed to artificial sea water (as a negative control) and one of six treatments (sterilized sea water, sea water from a channel at ebb tide, sea water from a channel at flood tide, sea water from seagrass habitat, tannic acid dissolved in sterilized sea water, or lignin dissolved in sterilized sea water). Larvae that reached a size of competency to settle (approximately 10 mm standard length) swam faster when exposed to lignin dissolved in sterilized sea water than in other treatments; smaller larvae showed no response. Olfactory preference (taxis) was tested using a paired-choice experiment. Settlement-size larvae preferred water from seagrass beds to artificial sea water. The observed chemokinesis and chemotaxis in response to lignin dissolved in sterilized sea water and sea water from a seagrass bed demonstrate that red drum larvae can distinguish and respond to different water masses and suggest that chemical stimuli from seagrass settlement habitat may aid in orientation and movement to or retention in suitable settlement sites. © 2015, Coastal and Estuarine Research Federation.
Heck K.L.,Dauphin Island Sea Laboratory |
Heck K.L.,University of South Alabama |
Fodrie F.J.,University of North Carolina at Chapel Hill |
Madsen S.,Atlantic States Marine Fisheries Commission |
And 2 more authors.
Marine Ecology Progress Series | Year: 2015
Temperatures are rising in most temperate and polar environments, and a welldocumented effect of this change is a poleward range shift by a wide variety of terrestrial and aquatic species. In the northern Gulf of Mexico (GOM), an increasing number of tropical species have recently become established among the extant warm-temperate fauna. These include a diversity of tropical fishes, manatees, green turtles, warm-water corals, and black mangroves. The impact of these species may be profound, primarily because temperate species are restricted from shifting northward by the North American land mass. Thus, as tropical species expand northward in the GOM, they must interact with the extant species and potentially compete for essential resources or become prey for each other. Here we focus on tropical immigrants capable of transforming the vast and highly productive seagrass systems of the northern GOM, emphasizing herbivorous parrotfishes and comparing their impact with endemic seagrass-resident fishes. Increased numbers of these herbivores (plus green turtles and manatees) would likely shift detritus-based food webs in seagrass meadows to webs dominated by direct consumption of seagrasses. We provide estimates of some expected consumption rates and effects of these tropically associated seagrass herbivores and predict that the consequences of the increased tropicalization of northern GOM seagrass meadows will be: substantially reduced standing crops and structural complexity of seagrass meadows; increased energy flux through grazing food webs; and a greatly reduced nursery role that will result in much smaller adult populations of those finfish and shellfish species that rely on seagrasses as nurseries. © Inter-Research 2015.
Lynch P.D.,National Oceanic and Atmospheric Administration |
Nye J.A.,State University of New York at Stony Brook |
Hare J.A.,National Oceanic and Atmospheric Administration |
Stock C.A.,National Oceanic and Atmospheric Administration |
And 4 more authors.
ICES Journal of Marine Science | Year: 2014
The term river herring collectively refers to alewife (Alosa pseudoharengus) and blueback herring (A. aestivalis), two anadromous fishes distributed along the east coast of North America. Historically, river herring spawning migrations supported important fisheries, and their spawning runs continue to be of cultural significance to many coastal communities. Recently, substantial declines in spawning run size prompted a petition to consider river herring for listing under the Endangered Species Act (ESA). The ESA status review process requires an evaluation of a species' response to multiple stressors, including climate change. For anadromous species that utilize a range of habitats throughout their life cycle, the response to a changing global climate is inherently complex and likely varies regionally. River herring occupy marine habitat for most of their lives, and we demonstrate that their relative abundance in the ocean has been increasing in recent years. We project potential effects of ocean warming along the US Atlantic coast on river herring in two seasons (spring and fall), and two future periods (2020-2060 and 2060-2100) by linking species distribution models to projected temperature changes from global climate models. Our analyses indicate that climate change will likely result in reductions in total suitable habitat across the study region, which will alter the marine distribution of river herring. We also project that density will likely decrease for both species in fall, but may increase in spring. Finally, we demonstrate that river herring may have increased sensitivity to climate change under a low abundance scenario. This result could be an important consideration for resource managers when planning for climate change because establishing effective conservation efforts in the near term may improve population resiliency and provide lasting benefits to river herring populations. © 2014 Published by Oxford University Press on behalf of International Council for the Exploration of the Sea.
Nesslage G.M.,Atlantic States Marine Fisheries Commission |
Wilberg M.J.,Post University
North American Journal of Fisheries Management | Year: 2012
Single-species surplus production models are often used to assess multispecies assemblages in data-poor situations where catch and effort data are insufficient to perform individual species assessments. We examined the performance of single-species surplus production models applied to aggregated multispecies assemblages and explored the incorporation of time-varying parameters to improve model estimates. We simulated the dynamics of three species with different intrinsic growth rates and survey catchabilities over 50 years in the presence of fishing and a single fishery independent survey. Schaefer surplus production models with and without time-varying growth rate and catchability were fitted to simulated data. We then compared the ability of each model to accurately estimate multispecies maximum sustainable yield and terminal year biomass and to accurately reflect overall trends in individual component stocks. All models produced biased estimates, but the accuracy of multispecies assemblage maximum sustainable yield was improved with the incorporation of time-varying parameters. The terminal biomass of the assemblage was best estimated by a basic production model in two of three scenarios. Multispecies assemblage trends were not reflective of all individual component species, resulting in situations in which some species were overexploited and others underexploited. Although the incorporation of time-varying parameters improved the accuracy of some estimates in this application, the direction and magnitude of bias may not be predictable unless the relative differences in growth rate and catchability among species in the assemblage are known. If single-species surplus production models are the only viable option for modeling assemblages, precautionary reference points should be adopted. Scaling the level of precaution to the range of growth rates among species in the assemblage is recommended. © American Fisheries Society 2012.
News Article | October 28, 2016
HOUSTON, TX--(Marketwired - October 27, 2016) - Omega Protein Corporation ( : OME), a nutritional product company and a leading integrated provider of specialty oils and specialty protein products, announced today that the Atlantic States Marine Fisheries Commission (ASMFC) has increased the annual harvest quota by 6.45 percent for the Atlantic menhaden fish meal/oil fisheries and bait fisheries. The decision to increase the quota is based on the continued strength of the Atlantic menhaden stock as it expands in its range up and down the Atlantic coastline. The new harvest quota will take effect for the 2017 Atlantic menhaden fishing season. "Omega Protein has responsibly harvested menhaden from these Atlantic waters for more than a century and no one has more at stake in a healthy, sustainable menhaden resource than we do. We were pleased by the ASMFC's judgment to increase the menhaden quota by 6.45 percent," said Bret D. Scholtes, Chief Executive Officer of Omega Protein. "A growing number of observed sightings of very large menhaden schools have validated the strong findings of the ASMFC's most recent assessment. This illustrates to us that there should be no doubt that the stock is robust and healthy enough for increased harvest." The increase brings the total annual amount of Atlantic menhaden that can be landed by Omega Protein and independent bait fisherman to 200,000 metric tons. It is also expected Virginia will maintain its 85 percent share of the coastwide allocation for its fish meal/oil fisheries and bait fisheries for the 2017 season. If Virginia maintains its current allocation split between fish meal/oil fisheries and bait fisheries, then the Company believes that in 2017 the Company's Atlantic fish catch limit will be approximately 152,000 metric tons. "Scientific analysis indicates that the ASMFC could have raised harvest levels beyond the 6.45 percent increase with no risk of overfishing. However, we understand the Commission's desire to take measured steps to insure the stock's continued health," Mr. Scholtes said. "Omega Protein remains committed to participating in future management actions, and is hopeful that the ASMFC will continue to derive its resource decisions based upon the best available science." Omega Protein Corporation ( : OME) is a century old nutritional product company that develops, produces and delivers healthy products throughout the world to improve the nutritional integrity of foods, dietary supplements and animal feeds. Omega Protein's mission is to help people lead healthier lives with better nutrition through sustainably sourced ingredients such as highly-refined specialty oils, specialty protein products and nutraceuticals. The Company operates seven manufacturing facilities located in the United States, Canada and Europe. The Company also operates more than 30 vessels to harvest menhaden, a fish abundantly found in the Atlantic Ocean and Gulf of Mexico. SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS: The statements contained in this press release that are not historical facts are forward-looking statements that involve a number of risks and uncertainties. Forward-looking information may be based on projections, predictions and estimates. Some statements in this press release may be forward-looking and use words like "may," "may not," "believes," "do not believe," "expects," "do not expect," "anticipates," "do not anticipate," "see," "do not see," or other similar expressions. The actual results of future events described in any of these forward-looking statements could differ materially from those stated in the forward-looking statements. Important factors that could cause actual results to be materially different from those forward-looking statements include, among others: (1) the Company's ability to meet its raw material requirements through its annual menhaden harvest, which is subject to fluctuations due to natural conditions over which the Company has no control, such as varying fish population, fish oil yields, adverse weather conditions, natural and other disasters and disease; (2) the impact of laws and regulations that may be enacted that may restrict the sale of the Company's products or the Company's operations, including the ASMFC restrictions on the Company's menhaden fishing operations referred to above, (3) the final laws or regulations implementing the ASMFC guidelines that may be adopted by the ASMFC member states which may differ materially from the ASMFC guidelines, (4) the timetable for implementation of these ASMFC guidelines by the ASMFC member states, (5) the allocation between the fish meal/oil fishery and bait fishery industries as may be finally approved by the Commonwealth of Virginia and the resulting limitations on the Company's Atlantic fish catch, and (6) the impact of worldwide supply and demand relationships on prices for the Company's products. Other factors are described in further detail in the Company's filings with the Securities and Exchange Commission, including its reports on Form 10-K, Form 10-Q and Form 8-K.
News Article | June 14, 2016
Just a few days after an abandoned dam was dismantled near Albany in New York, swarms of herring swam and spawned into the waters of a Hudson River tributary for the first time in nearly nine decades. The industrial dam located on the Wynants Kill was removed in the hopes of saving the spawning habitat of herring and other ocean-going species. All of these species have suffered from habitat loss, overfishing and pollution. The removal of the rusted steel dam is only the first of many barriers expected to be dismantled in the Hudson tributaries and other parts of the country. According to the advocacy group American Rivers, the Wynants Kill project is part of a larger movement that has already taken away nearly 250 dams across the United States since 2012. Frances Dunwell, coordinator of the state's Hudson River Estuary Program, says most of the 1,500 dams in the estuary watershed are no longer in use. "One of the key items on our to-do list by 2020 is to remove as many of these barriers as possible," says Dunwell. Extending 150 miles north from the Atlantic Ocean, the Hudson estuary is a vital breeding ground for herring species such as the alewife and the American shad. The streams used to flash silver with herring during spawning runs in Colonial times. However, the dams built during the Industrial Revolution caused populations of herring to move along the Atlantic Coast from South Carolina to Maine. Overfishing and pollution in recent years worsened the situation. Three years ago, the Atlantic States Marine Fisheries Commission required 15 states to submit plans for restoring the spawning and nursery habitat in the estuary. At that time, climate change and dams were cited as the biggest threats. Biology Professor John Waldman of Queens College says dams are artifacts of the Industrial Revolution and are persistent in causing harm. He says experts should decide which dams are still useful and which should be dismantled. Meanwhile, Dunwell says at least six privately owned unused dams are targets for removal. Furthermore, NY's Department of Environmental Conservation will offer private owners grants and technical support for the restoration project. On Maine's Penobscot River, a hydropower dam was recently dismantled to restore a major river. The removal of two dams plus the construction of a fish bypass opened at least 1,000 miles (1,609 km) of habitat for 11 species of sea-run fish. Most projects center on removing small dams that have outlived their original purposes. Last spring, American shad swam up in Delaware's White Clay Creek for the first time. In 1777, a mill owner had built a timber-and-stone dam that obstructed the fish. It was removed in 2014 with the help of $200,000 federal and conservation group funding. © 2016 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | November 9, 2015
The lobster population has sunk to the lowest levels on record in southern New England waters, affecting once-productive fishing grounds off Rhode Island and southern Massachusetts. The catch off Rhode Island is a third of the size that it was in the late 1990s, and it has all but disappeared off Connecticut. A science committee of the Atlantic States Marine Fisheries Commission is working on a report about the lobster stock that the commission's lobster board will see in February. The board could then make a decision about the future of the fishery, including changing quotas or enacting new restrictions. William Adler, a longtime Massachusetts lobstermen and a member of the lobster board, said that a moratorium is not likely on the table but that something needs to be done to conserve the region's lobsters, which are beloved by restaurant diners. "You can't let them go free, and you can't shut them down," he said. "Both extremes are not workable." The declines in lobsters off southern New England are largely in response to continued fishing pressure and adverse environmental conditions, including higher water temperatures, the commission said in a summary of a report it issued about the subject this summer. The outlook for lobsters is much better in Maine, by far the most productive lobster fishing state in the country. Fishermen there have landed more than 100 million pounds of lobster for four years in a row. Overall, lobster availability and price have both been fairly high in recent months. The high price has allowed fishermen to reinvest in gear and boats, and new restrictions would curtail that growth, said Beth Casoni, executive director of the Massachusetts Lobstermen's Association. "We want to make sure the measures aren't overly burdensome," she said. "You could lose infrastructure—piers, bait suppliers, marine stores."