Animal Sciences Commons^™

A General Theory Of Age-Length Keys: Combining The Forward And Inverse Keys To Estimate Age Composition From Incomplete Data, Lisa E. Ailloud, John M. Hoenig

VIMS Articles

There are two approaches to estimating age composition from a large number of length observations and a limited number of age determinations: the forward and the inverse age-length keys. The forward key looks at the distribution of age within each length bin while the inverse key looks at the distribution of length at each age. The former is more precise but has stringent requirements for the way data are collected. The latter approach is more widely applicable. We review the theory of the two keys with particular attention to necessary assumptions and the restrictions on when the methods are applicable. …

Monitoring The Abundance Of American Shad And River Herring In Virginia's Rivers - 2018 Annual Report, Eric J. Hilton, Robert Latour, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee

Reports

This report describes the results of the twenty-first year of a continuing study to estimate the relative abundance and assess the status of American shad (Alosa sapidissima) stocks in Virginia by monitoring the spawning runs in the James, York and Rappahannock rivers in spring 2018, evaluating hatchery programs, and contributing to coast-wide assessments (ASMFC 2007). We also report on two fishery-independent monitoring programs using anchor gillnets in the Rappahannock River (year 1) and the Chickahominy River (year 4; a major tributary of the James River), to determine relative abundance and stock structure for the adult spawning run of river herring …

Estimating Age Composition For Multiple Years When There Are Gaps In The Ageing Data: The Case Of Western Atlantic Bluefin Tuna, Lisa E. Ailloud, Matthew V. Lauretta, John F. Walter Iii, John M. Hoenig

VIMS Articles

Age–length key (ALK) methods generally perform well when length samples and age samples are representative of the underlying population. It is unclear how well these methods perform when lengths are representative but age samples are sparse (i.e. age samples are small or missing in many years, and some length groups do not have any age observations). With western Atlantic bluefin tuna, the available age data are sparse and have been, for the most part, collected opportunistically. We evaluated two methods capable of accommodating sparse age data: a novel hybrid ALK (combining forward ALKs and cohort slicing) and the combined forward-inverse …

The Status Of Virginia’S Public Oyster Resource 2018, Melissa Southworth, Roger L. Mann

Reports

This report summarizes data collected during 2018 in the Virginia portion of the Chesapeake Bay. The report is composed of two parts, part one, oyster recruitment (shell string) in Virginia and part two, dredge survey of selected oyster bars in Virginia

Virginia Shark Identification Guide, Multispecies Research Group, Virginia Institute Of Marine Science

Reports

Illustrated with distribution maps and species characteristics.

Table of Contents:

Atlantic Sharpnose Shark | Bigeye Thresher Shark | Bignose Shark | Blacknose Shark | Blacktip Shark | Blue Shark | Bluntnose Sixgill Shark | Bonnethead Bull Shark | Dusky Shark | Finetooth Shark | Great Hammerhead Shark | Great White Shark | Gulper Shark | Lemon Shark | Longfin Mako Shark | Night Shark | Oceanic Whitetip Shark | Porbeagle | Sandbar Shark | Sand Tiger Shark | Scalloped Hammerhead Shark | Sharpnose Sevengill Shark | Shortfin Mako Shark | Silky Shark | Smooth Dogfish | Smooth Hammerhead Shark | …

Estimating Relative Abundance Of Young-Of-The-Year American Eel, Anguilla Rostrata, In The Virginia Tributaries Of Chesapeake Bay, Spring 2018, Troy D. Tuckey, Mary C. Fabrizio

Reports

American Eel (Anguilla rostrata) is a valuable commercial species along the Atlantic coast of North America from New Brunswick to Florida. In the U.S., harvests have declined, with similar patterns occurring in the Canadian Maritime Provinces (Meister and Flagg 1997). An average of 62% of the annual landings of U.S. commercial harvest since 1993 have come from the Chesapeake Bay (personal communication from the National Marine Fisheries Service, Fisheries Statistics Division, 9 February 2015). In 2013, Virginia commercial landings were approximately 100,298 lbs; since mandatory reporting began in 1993, average annual landings in Virginia have been 193,200 lbs or 19% …

Virginia Fishery Resource Grant Program 2018, Virginia Fishery Resource Grant Program, Virginia Institute Of Marine Science

Reports

No abstract provided.

Examining Derelict Pot Impacts On Harvest In A Commercial Blue Crab Callinectes Sapidus Fishery, James A. Delbene, Donna M. Bilkovic, Andrew M. Scheld

VIMS Articles

Pot fisheries occur worldwide with a significant proportion of the gear becoming derelict. Derelict pots induce detrimental ecological and economic impacts, and more recently were found to reduce blue crab harvests in the Chesapeake Bay commercial fishery. We simulated the presence of derelict pots near actively fished pots in seasonal field experiments to quantify the effect derelict pots have on blue crab harvest. Derelict pots reduced harvests by 30% during the summer, but not during the fall. Female blue crab capture rates were consistently lower when derelict pots were present; while capture rates of the less abundant males were not …

Evaluation Of Striped Bass Stocks In Virginia: Monitoring And Tagging Studies, 2019 Progress Report - 1 December 2018 - 31 November 2019, Robert J. Latour, Christopher F. Bonzek, James Gartland

Reports

This report presents the results of striped bass (Morone saxatilis) tagging and monitoring activities in Virginia during the period 1 December 2018 through 31 November 2019. It includes an assessment of the biological characteristics of striped bass taken from the 2019 spring spawning run and estimates of annual survival and fishing mortality based on annual spring tagging. The information contained in this report is required by the Atlantic States Marine Fisheries Commission and is used to implement a coordinated management plan for striped bass in Virginia, and along the eastern seaboard.

This report includes 2018 striped bass Benchmark Assessment data.

Climate Change Enhances Disease Processes In Crustaceans: Case Studies In Lobsters, Crabs, And Shrimps, Jeffrey D. Shields

VIMS Articles

Climate change has resulted in increasing temperature and acidification in marine systems. Rising temperature and acidification act as stressors that negatively affect host barriers to infection, thus enhancing disease processes and influencing the emergence of pathogens in ecologically and commercially important species. Given that crustaceans are ectotherms, changes in temperature dominate their physiological and immunological responses to microbial pathogens and parasites. Because of this, the thermal ranges of several crustacean hosts and their pathogens can be used to project the outcomes of infections. Host factors such as molting, maturation, respiration, and immune function are strongly influenced by temperature, which in …

Tracking Triploid Mortalities Of Eastern Oysters Crassostrea Virginica In The Virginia Portion Of The Chesapeake Bay, Eric Guevelou, Ryan Carnegie, Ja Moss, Karen Hudson, Kimberly S. Reece, Molly M. Rybovich, Standish K. Allen Jr.

VIMS Articles

Since 2012, aquacultured eastern oysters Crassostrea virginica have been reported by oyster farmers to display mortality approaching 30%, and in some cases 85%, in areas of the lower Chesapeake Bay, VA. Based on accounts from industry, this mortality has typically affected 1-y-old oysters between May and early July, and has tended to occur in triploid oysters, which represent the vast bulk of production in the area. During this period, samples submitted for pathology have not revealed the presence of major pathogens as a cause. In 2015, to gain deeper insight into this mortality and determine whether specific sites, ploidy condition, …

The Impacts Of Warming And Hypoxia On The Performance Of An Obligate Ram Ventilator, Daniel P. Crear, Richard Brill, Peter G. Bushnell, Robert J. Latour, Gail D. Schwieterman, Rachel M. Steffen, Kevin C. Weng

VIMS Articles

Climate change is causing the warming and deoxygenation of coastal habitats like Chesapeake Bay that serve as important nursery habitats for many marine fish species. As conditions continue to change, it is important to understand how these changes impact individual species' behavioral and metabolic performance. The sandbar shark (Carcharhinus plumbeus) is an obligate ram-ventilating apex predator whose juveniles use Chesapeake Bay as a nursery ground up to 10 years of age. The objective of this study was to measure juvenile sandbar shark metabolic and behavioral performance as a proxy for overall performance (i.e. fitness or success) when exposed to warm …

Nursery Habitat Quality Assessed By The Condition Of Juvenile Fishes: Not All Estuarine Areas Are Equal, Ryan W. Schloesser, Mary C. Fabrizio

VIMS Articles

High-quality nursery habitats support greater numbers of juveniles that survive to adulthood, but characteristics underlying high-quality habitats remain elusive because their productivity varies spatially and temporally and may be species-specific. Fish condition is an energy-integrative measure of ecological interactions, stress, and activity within a habitat, such that juvenile fish condition is representative of the quality of nursery habitats. We apply spatially explicit models to examine patterns in nursery habitat quality of Virginia estuaries based on nutritional condition for Atlantic croaker Micropogonias undulatus, summer flounder Paralichthys dentatus, and striped bass Morone saxatilis. Environmental factors (water temperature, dissolved oxygen, salinity, and depth) …

Tooth Development And Replacement In The Atlantic Cutlassfish, Trichiurus Lepturus, With Comparisons To Other Scombroidei, Katherine E. Bemis, Samantha M. Burke, Carl A. St John, Eric J. Hilton, William E. Bemis

VIMS Articles

Atlantic Cutlassfish, Trichiurus lepturus, have large, barbed, premaxillary and dentary fangs, and sharp dagger-shaped teeth in their oral jaws. Functional teeth firmly ankylose to the dentigerous bones. We used dry skeletons, histology, SEM, and micro-CT scanning to study 92 specimens of T. lepturus from the western North Atlantic to describe its dentition and tooth replacement. We identified three modes of intraosseous tooth replacement in T. lepturus depending on the location of the tooth in the jaw. Mode 1 relates to replacement of premaxillary fangs, in which new tooth germs enter the lingual surface of the premaxilla, develop horizontally, and rotate …

Monitoring Demographics Of A Commercially Exploited Population Of Shovelnose Sturgeon In The Wabash River, Illinois/Indiana, Usa, Jessica L. Thornton, Vaskar Nepal, Leslie D. Frankland, Craig R. Jansen, Jana Hirst, Robert E. Colombo

VIMS Articles

Shovelnose sturgeon (Scaphirhynchus platorynchus, Rafinesque, 1820) in the Wabash River, Illinois/Indiana, USA, provide an important recreational sport and commercial caviar fishery. In fact, it is one of the last commercially viable populations for sturgeon roe harvest. Due to increased demand in the caviar trade and endangered species legislation that protect shovelnose sturgeon in only a portion of their range, efforts of the roe harvest market may continue to divert toward unprotected populations like the shovelnose sturgeon in the Wabash River. Previous studies have shown that increased harvest pressure in this species can affect the age‐at‐maturation and result in recruitment …

Evaluating Summer Flounder Spatial Sex-Segregation In A Southern New England Estuary, Joseph A. Langan, M. Conor Mcmanus, Adena J. Schonfeld, Corinne L. Truesdale, Jeremy S. Collie

VIMS Articles

Marine fish species can exhibit sex-specific differences in their biological traits. Not accounting for these characteristics in the stock assessment or management of a species can lead to misunderstanding its population dynamics and result in ineffective regulatory strategies. Summer Flounder Paralichthys dentatus, a flatfish that supports significant commercial and recreational fisheries along the northeastern U.S. shelf, expresses variation in several traits between the sexes, including growth and habitat preference. To further understand these patterns, 1,302 Summer Flounder were collected and sexed in 2016 and 2017 from fisheries-independent surveys conducted in Rhode Island state waters. Female flounder were more prevalent …

Genome-Wide Snps Resolve Spatiotemporal Patterns Of Connectivity Within Striped Marlin (Kajikia Audax), A Broadly Distributed And Highly Migratory Pelagic Species, Nadya Mamoozadeh, John Graves, Jan Mcdowell

VIMS Articles

Genomic methodologies offer unprecedented opportunities for statistically robust studies of species broadly distributed in environments conducive to high gene flow, providing valuable information for wildlife conservation and management. Here, we sequence restriction site‐associated DNA to characterize genome‐wide single nucleotide polymorphisms (SNPs) in a broadly distributed and highly migratory large pelagic fish, striped marlin (Kajikia audax). Assessment of over 4,000 SNPs resolved spatiotemporal patterns of genetic connectivity throughout the species range in the Pacific and, for the first time, Indian oceans. Individual‐based cluster analyses identified six genetically distinct populations corresponding with the western Indian, eastern Indian, western South Pacific, …

Virginia Shellfish Aquaculture Situation And Outlook Report: Results Of The 2018 Virginia Shellfish Aquaculture Crop Reporting Survey, Karen Hudson, Virginia Sea Grant Marine Advisory Program

Reports

No abstract provided.

Satellites, Seagrass, And Blue Crabs: Understanding Inter-Annual Fluctuations And Linkages In The York River, Kristen Bachand

Dissertations, Theses, and Masters Projects

To protect and manage ecosystems over large spatial scales, repeated mapping with remote sensing, such as aerial photography, is valuable, but several potential problems need to be overcome to generate accurate maps. For instance, to monitor submerged aquatic vegetation (SAV), such as seagrass, satellite imagery must often capture seasonal and interannual variation as well as disturbances. We used a model system, SAV and the blue crab Callinectes sapidus in the lower Chesapeake Bay, to examine (i) if Planet Lab (PL) satellite imagery can be used to accurately estimate SAV coverage by comparing PL images coincident with those of the VIMS …

Estimation Of Juvenile Striped Bass Relative Abundance In The Virginia Portion Of Chesapeake Bay. Annual Progress Report: 2018-2019, Brian K. Gallagher, Mary C. Fabrizio, Troy D. Tuckey

Reports

The 2018 Striped Bass juvenile abundance index was 10.72 and was not significantly different than the reference mean of 7.77 from 1980-2009. Abundance indices in the James and York river systems in 2018 were average compared to their individual reference means (1980-2009), whereas abundance was above average in the Rappahannock River. Relatively high catches of young‐of‐the‐year Striped Bass at downriver sites in 2018 suggested Striped Bass were displaced downstream of their typical core nursery areas, likely due to high volumes of freshwater discharge and low salinities before and during the sampling period. Juvenile White Perch abundance indices in 2018 were …

2019 Annual Report Estimating Relative Juvenile Abundance Of Ecologically Important Finfish In The Virginia Portion Of Chesapeake Bay (1 July 2018 – 30 June 2019), Troy D. Tuckey, Mary C. Fabrizio

Reports

EXECUTIVE SUMMARY

The Trawl Survey provides crucial data to state, regional, and national fisheries management agencies, including the Virginia Marine Resources Commission (VMRC), the Atlantic States Marine Fisheries Commission (ASMFC), the Mid-Atlantic Fisheries Management Council (MAFMC), and the National Marine Fisheries Service (NMFS). The MAFMC recognizes the juvenile trawl survey as one of the key predictors of Summer Flounder recruitment. Annual indices of juvenile abundance have been generated from trawl survey data for species of key recreational and ecological importance in the Virginia portion of Chesapeake Bay. These include Spot, Atlantic Croaker, Weakfish, Summer Flounder, Black Sea Bass, Scup, Striped …

Testing The Efficiency Of Wire Reinforced Catfish Pots And Comparing Horizontal And Vertical Configurations To Catch Invasive Catfish In The James River, Va, Matt Balazik, George Trice, Charles Frederickson, Martin Balazik

Reports

The Chesapeake Bay is currently inundated with invasive blue catfish (BCF) which are a serious threat to the ecosystem balance ofthe watershed.The only reasonableway to reduce BCF numbers and biomass is by utilizing new and improving traditional BCF commercial fisheriestechniqueswith emphasis on removing small BCF. In the Mississippi region pots set in a vertically orientation are easier to fish and outperform pots set horizontally. The purpose of this project was to see how pots set in two vertical orientationswould perform compared to thetraditional horizontal orientation. During the project 7275lbs of nonnative catfish were harvested, 3088in vertical pots and 4187lbs in …

Vims Shark Longline Annual Report - 2019, Multispecies Research Group, Virginia Institute Of Marine Science

Reports

Report indicates the number of species caught, retained, released and tagged in the longline surveys.