John A. Musick

Virginia Institute of Marine Science · Department of Fisheries Science

This report sets out the details of the MSC full assessment for the US Acadian Redfish, Haddock, and Pollock fisheries against the MSC Principles and Criteria for Sustainable Fishing. The report details the background, results of the assessment, the rationales that substantiate the scores for each performance indicator, conditions and milestones fo...

The growth and reproductive characteristics of Longnose Gar, Lepisosteus osseus, from the tidal portions of the major rivers in Virginia were analyzed using a three-dimensional population demographic model. This was the first study concerning Longnose Gar to test multiple growth models, and the biphasic double von Bertalanffy model best fit the dat...

This study examines the potential uncertainty in survey biomass estimates of Spiny Dogfish Squalus acanthias in the Northeast U.S. Continental Shelf Large Marine Ecosystem (NES LME). Diel catch-per-unit-effort (CPUE) estimates are examined from the Northeast Fisheries Science Center bottom trawl surveys conducted during autumn (1963–2009) and sprin...

When identifying potential trophic cascades, it is important to clearly establish the trophic linkages between predators and prey with respect to temporal abundance, demographics, distribution, and diet. In the northwest Atlantic Ocean, the depletion of large coastal sharks was thought to trigger a trophic cascade whereby predation release resulted...

The Chesapeake Bay and Atlantic Ocean waters of Virginia, USA include seasonal developmental and migratory areas for the Kemp’s ridley sea turtle (Lepidochelys kempii). The species historically comprised 10% of the state’s sea turtle strandings, but that proportion has risen to 20-30%. Diet analyses are useful tools for examining habitat use and ec...

Diet analysis is critical in understanding the flow of energy within marine food webs and is necessary for trophic ecosystem modeling and subsequent ecosystem‐based management recommendations. This study represents the first comprehensive diet description for the Barndoor Skate Dipturus laevis , the largest rajid species found on the continental sh...

Chondrichthyans are largely absent in abyssal (> 3000 m) habitats in most regions of the world ocean and are uncommon below 2000 m. The deeper-living chondrichthyans include certain rajids, squaliforms and holocephalans. Several hypotheses have been erected to explain the absence of chondrichthyans from the abyss. These are mostly based on energeti...

Modes of reproduction and embryonic development vary greatly among the elasmobranchs, and prior studies have suggested that the energetic toll of embryogenesis in lecithotrophic species depletes embryonic organic matter by 20% or more. Matrotrophic species experience a lesser reduction or an increase in organic matter during embryogenesis. To inves...

Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus, Acipenseridae) populations in the United States were listed as either endangered or threatened under the Endangered Species Act in 2012. Because of the endangered/threatened status, a better understanding of Atlantic sturgeon life-history behavior and habitat use is important for effective managem...

Commercial fishermen have argued that localized concentrations of spiny dogfish (Squalus acanthias) in the northeast U.S. shelf large marine ecosystem (NES LME) have impeded their fishing operations when monitoring surveys estimated lower relative abundances. Fishery-dependent and -independent data were analyzed simultaneously to examine whether in...

Increased commercial importance of spiny dogfish (Squalus acanthias) combined with an often debated, and controversial, ecological impact has warranted an investigation of the relationship among distribution, environment, and prey to better understand the species ecology and inform management. To elucidate mechanisms behind distributional changes,...

Vertebrae of most deep-water sharks are too poorly calcified to record visible growth bands and therefore are not useful for age determination. Most dogfish species (Order: Squaliformes) possess dorsal finspines and several recent studies have shown that these structures offer potential for age determination. Age validation should be central to any...

Declines in abundance of commercially valuable groundfish have highlighted the ecological and commercial importance of previously underutilized elasmobranchs in the Northeast (US) shelf large marine ecosystem (NES LME). Seasonal distributions and ontogenetic habitats of one such species, spiny dogfish (Squalus acanthias), were investigated using No...

The Data Deficient chondrichthyan species that are potentially threatened. DOI: http://dx.doi.org/10.7554/eLife.00590.024

(A) IUCN Red List status of chondrichthyans in the fin trade, including (i) families with the most-valued fins, and (ii) the most prevalent species utilized in the Hong Kong fin trade. (B) Chondrichthyan species threatened by (i) control measures, and (ii) habitat destruction and degradation, pollution or climate change with the corresponding IUCN...

Number and IUCN Red List status of chondrichthyan species in IUCN Red List categories by family (alphabetically within each order).DOI: http://dx.doi.org/10.7554/eLife.00590.013

The rapid expansion of human activities threatens ocean-wide biodiversity. Numerous marine animal populations have declined, yet it remains unclear whether these trends are symptomatic of a chronic accumulation of global marine extinction risk. We present the first systematic analysis of threat for a globally distributed lineage of 1,041 chondricht...

Age, growth, and reproduction were studied in goose­ fish Lophius americanus collected from National Marine Fisheries Ser­ vice groundfish surveys and com­ mercial fishing cruises between Georges Bank and Cape Hatteras in the western North Atlantic. Age and growth of L. americanuswere deter­ mined from vertebral annuli, which became visible at the...

Chesapeake Bay is the largest estuary in the USA and comprises vast areas of polyhaline to freshwater, tidal fish habitat. The Bay experiences large temperature differences between winter and summer, which in combination with the variety of salinities enables approximately 240 species of fish to be temporary inhabitants. This dynamic environment le...

The number of Sandbar Sharks Carcharhinus plumbeus in the western North Atlantic Ocean has experienced a drastic decline since the early 1980s, reaching a minimum during the early 1990s. Catch rates in the early 1990s were a mere 25% of those during the 1980s. According to several fishery‐independent surveys, the low point in Sandbar Shark abundanc...

The seasonal movements of Lepisosteus osseus (Longnose Gar) are largely unknown. The goal of this project was to characterize spawning movements and seasonal distributions by using acoustic tagging methods and examining historical catch records from a trawl survey. This is the first time that movements have been studied for an estuarine population...

Seasonal and decadal movement patterns, environmental preference and distributional changes of spiny dogfish (Squalus acanthias) were examined along the northeast continental shelf from 1963 to 2009. Data were obtained from annual autumn and spring bottom trawl surveys conducted by the National Marine Fisheries Service (NMFS). Influences of bottom...

A modern synthesis of the biology of Chondrichthyans, Biology of Sharks and Their Relatives, Second Edition discusses significant advances in the development and application of new molecular techniques to the understanding of the phylogenetic relationships among and between these groups. The book considers the effect of global changes on the status...

Categories in which RMUs for each species occurred (including critical data needs RMUs). Categories: HR-HT = High risk-High threats; HR-LT = High risk-Low threats; LR-LT = Low risk-Low threats; LR-HT = Low risk-High threats. (DOCX)

Paired risk and threats scores for RMUs of each marine turtle species. (A) loggerheads (Caretta caretta), (B) green turtles (Chelonia mydas), (C) leatherbacks (Dermochelys coriacea, (D) hawskbills (Eretmochelys imbricata), (E) olive ridleys (Lepidochelys olivacea), (F) Kemp's ridleys (Lepidochelys kempii) and flatbacks (Natator depressus). Vertical...

Scoring system for population size criterion in risk matrix. Numbers are average annual nesting females for the most recent survey data available. (DOCX)

List of Regional Management Unit (RMU) codes used in Fig. 1. Species: Caretta caretta, loggerhead; Chelonia mydas, green turtle; Dermochelys coriacea, leatherback; Eretmochelys imbricata, hawksbill; Lepidochelys kempii, Kemp's ridley; Lepidochelys olivacea, olive ridley; Natator depressus, flatback. (DOCX)

Bibliography of literature used to score risk and threats criteria. (PDF)

Areas of Competence for Regional Fishery Bodies (RFB) with a management mandate. RFB acronyms: CCAMLR: Commission on the Conservation of Antarctic Marine Living Resources; CCBSP: Convention on the Conservation and Management of Pollock Resources in the Central Bering Sea; CCSBT: Commission for the Conservation of Southern Bluefin Tuna; GFCM: Genera...

Complete dataset used to score all criteria in Risk and Threats matrices, as well as data uncertainty scores. (XLS)

Complete list of SWOT – The State of the World's Sea Turtles data providers. (XLS)

Where conservation resources are limited and conservation targets are diverse, robust yet flexible priority-setting frameworks are vital. Priority-setting is especially important for geographically widespread species with distinct populations subject to multiple threats that operate on different spatial and temporal scales. Marine turtles are widel...

Sharks and their relatives, the batoids comprise the elasmobranch fishes, a group of more than 1,100 species, of which more than 400 are sharks. Most elasmobranchs have slow rates of growth, late age-at-maturity, and low fecundity compared to bony fishes. The history of most directed shark and ray fisheries around the world has been one of over-har...

The resting metabolic rates (R(R)) of western North Atlantic Ocean sciaenids, such as Atlantic croaker Micropogonias undulatus, spot Leiostomus xanthurus and kingfishes Menticirrhus spp., as well as the active metabolic rates (R(A)) of M. undulatus and L. xanthurus were investigated to facilitate inter and intraspecific comparisons of their energet...

From otter trawl catches in the Middle Atlantic Bight, blue hake, Antimora rostrata, were found at depths of 790 to at least 2930 m in the Norfolk Canyon area; maximum abundance was between 1300 and 2500 m. Available data indicate that the blue hake is more abundant in the western than the eastern North Atlantic. Males were smaller in average size...

Triglops murrayi was taken frequently in the Gulf of Maine during all sampling seasons. Ripe individuals were taken in October and total numbers of ova ranged from 1965 to 2739 per female. Diameters of ova varied from 0.20 to 2.00 mm and each female may lay several complements of eggs over a long spawning season. The mode of reproduction of T. murr...

Otter-trawl records and midwater-trawl catches suggested that some mesopelagic fishes are permanent members of the midwater fauna of the Gulf of Maine rather than strays. Benthosema glaciale, Ceratoscopelus maderensis, Myctophum punctatum, and Maurolicus muelleri, cold water or ubiquitous species, occur in the Gulf throughout the year, and warmwate...

Fecundity of the American eel, Anguilla rostrata, was estimated from 21 specimens migrating from Chesapeake Bay during November 1970. The relationship between total length and fecundity is log y = −4.29514 + 3.74418 log x where y is fecundity and x is total length (mm) and between total weight and fecundity is log y = 3.22990 + 1.1157 log x where y...

Restriction fragment length polymorphism analysis of mitochondrial DNA was used to investigate genetic population structure within the shortfin mako (Isurus oxyrinchus). Tissue samples from 21-30 shortfin makos were collected from each of five locations, two within the North Atlantic, one in the South Atlantic, one in the North Pacific, and one in...

The southern stingray, Dasyatis americana, displays aplacental viviparity, embryos being retained in the maternal uterus throughout gestation and initially nourished by the yolk sac contents. During gestation the uterus develops vascularized appendages, trophonemata, that secrete viscous nutrient histotroph that is subsequently ingested by the embr...

In the fetal southern stingray, Dasyatis americana, both the stomach and spiral intestine function early in development to digest and absorb nutrient histotroph elaborated by uterine villi termed trophonemata. The gastric mucosa consists of a surface columnar mucous epithelium that is confluent with gastric pits or foveolae. Gastric glands are popu...

About half of the extant shark species occur only in deep waters (defined as.200mdepth), yet few published studies on sharks include these taxa. As fisheries worldwide enter deeper waters, the provision of biological data for these little-known taxa is critical to management and conservation. The shortspine spurdog, Squalus cf. mitsukurii, is an ab...

Summary of Regional Management Units (RMUs) for marine turtles worldwide, including number of nesting sites and genetic stocks contained within each RMU. (DOC)

Metadata associated with each layer synthesized to generate Regional Management Units. (XLS)

Complete list of SWOT – The State of the World's Sea Turtles data providers. (XLS)

Background: Resolving threats to widely distributed marine megafauna requires definition of the geographic distributions of both the threats as well as the population unit(s) of interest. In turn, because individual threats can operate on varying spatial scales, their impacts can affect different segments of a population of the same species. There...

Multiple paternity (MP) has been shown to be widespread in elasmobranch fishes although its prevalence and the number of sires per litter vary considerably among species. In the squaloid shark Squalus acanthias, MP has been reported, but whether it is a common feature of the species’ reproductive strategy is unknown. In this study, we determined th...

Reproduction in marine fishes exhibits a remarkable level of biological diversity and sophistication. Nowhere is this more evident than in the chondrichthyans, which share the character of an entirely cartilaginous skeleton and constitute one of the two major groups of extant fishes. Chondrichthyans diverged from bony fishes early in the evolutiona...

Assessing Biodiversity Declines Understanding human impact on biodiversity depends on sound quantitative projection. Pereira et al. (p. 1496 , published online 26 October) review quantitative scenarios that have been developed for four main areas of concern: species extinctions, species abundances and community structure, habitat loss and degradati...

Maintaining optimal visual performance is a difficult task in photodynamic coastal and estuarine waters because of the unavoidable tradeoffs between light sensitivity and temporal resolution, yet the visual systems of coastal piscivorous fishes remain understudied despite differences in ecomorphology and microhabitat use. We therefore used electror...

The effectiveness of recovery plans for threatened and endangered species has been questioned in academic and political domains. A comprehensive assessment of species recovery plans concluded that quantification and prioritization of threats have received insufficient attention, which contributes to the failure of some plans. On the basis of this a...

The sandbar shark, Carcharhinus plumbeus, is a large, cosmopolitan, coastal species. Females are thought to show philopatry to nursery grounds while males potentially migrate long distances, creating an opportunity for male-mediated gene flow that may lead to discordance in patterns revealed by mitochondrial DNA (mtDNA) and nuclear markers. While t...

Maintaining optimal visual performance is a difficult task in photodynamic coastal and estuarine waters because of the unavoidable tradeoffs between luminous sensitivity and spatial and temporal resolution, yet the visual systems of coastal piscivores remain understudied despite differences in their ecomorphology and microhabitat use. We therefore...