Gordon T. Waring

Age, Growth, and Mortality of the Little Skate off the Northeast Coast of the United States

Abstract Age, growth, mortality, and yield per recruit of the little skate Raja erinacea in the Georges Bank-Delaware Bay region were investigated from trawl-survey data collected during 1968–1978. Eight age groups were observed in the population. The parameters of the von Bertalanffy growth equation are asymptotic length L∞ = 52.73 cm; growth coefficient K = 0.352; and hypothetical age at zero length t0 = -0.449 years. The length-weight relationship for both sexes combined over seasons is log10W = -2.641 + 3.229 log10L, where length L is in centimeters and weight W is in grams. Estimates of total instantaneous mortality rates Z for fully recruited ages (age 5 and older) ranged from 0.54 to 1.76 between 1968 and 1978. Natural-mortality values M ranged from 0.4 to 0.5; fishing-mortality values F ranged from 0.14 to 1.36, depending on the value of M assumed. Received May 13, 1983 Accepted March 21, 1984

U.S. Atlantic and Gulf of Mexico marine mammal stock assessments, 2013

1National Marine Fisheries Service, 166 Water St., Woods Hole, MA 02543 2National Marine Fisheries Service, 75 Virginia Beach Dr., Miami, FL 33149 3National Marine Fisheries Service, 219 Ft. Johnson Rd., Charleston, SC 29412 4National Marine Fisheries Service, 3209 Frederic St., Pascagoula, MS 39567 5Mote Marine Laboratory, 1600 Ken Thompson Pkwy., Sarasota, FL 34236 6Sea World, Inc., 7007 Sea World Dr., Orlando, FL 32821

A Population Assessment of Butterfish, Peprilus triacanthus, in the Northwestern Atlantic Ocean

Abstract Reported landings of butterfish, Peprilus triacanthus (Peck), in the Northwest Atlantic Ocean increased from 3,209 t in 1964 to a peak of 19,454 t in 1973. Most of the catch during the period was taken by vessels from Japan, the United States, Russia, and Poland. Unreported butterfish by-catches in the long-finned squid, Loligo pealei, fisheries of several nations, particularly Spain and Italy, were probably significant additional sources of butterfish mortality. Available scientific evidence indicates that during 1968–1976, fishing mortality rates increased, while the mean weight of individuals in the exploitable population and average age at capture generally declined. Exploitation rate (E) during 1968–1975 averaged 0.31. Yield-per-recruit studies conducted under an assumed instantaneous rate of natural mortality (M) of 0.8 suggest Emax (exploitation rate resulting in maximum yield per recruit) and E0.1 (exploitation rate generating a marginal increase in yield per recruit of 0.1 of that from a...

Google Haul Out: Earth Observation Imagery and Digital Aerial Surveys in Coastal Wildlife Management and Abundance Estimation

Abstract As the sampling frequency and resolution of Earth observation imagery increase, there are growing opportunities for novel applications in population monitoring. New methods are required to apply established analytical approaches to data collected from new observation platforms (e.g., satellites and unmanned aerial vehicles). Here, we present a method that estimates regional seasonal abundances for an understudied and growing population of gray seals (Halichoerus grypus) in southeastern Massachusetts, using opportunistic observations in Google Earth imagery. Abundance estimates are derived from digital aerial survey counts by adapting established correction‐based analyses with telemetry behavioral observation to quantify survey biases. The result is a first regional understanding of gray seal abundance in the northeast US through opportunistic Earth observation imagery and repurposed animal telemetry data. As species observation data from Earth observation imagery become more ubiquitous, such methods provide a robust, adaptable, and cost‐effective solution to monitoring animal colonies and understanding species abundances.

Saxitoxin increases phocine distemper virus replication upon in-vitro infection in harbor seal immune cells

Several marine mammal epizootics have been closely linked to infectious diseases, as well as to the biotoxins produced by harmful algal blooms (HABs). In two of three saxitoxin (STX) associated mortality events, dolphin morbillivirus (DMV) or phocine distemper virus (PDV) was isolated in affected individuals. While STX is notorious for its neurotoxicity, immunotoxic effects have also been described. This study investigated the role of STX in altering immune function, specifically T lymphocyte proliferation, in harbor seals (Phoca vitulina concolor) upon in-vitro exposure. In addition, the study also examined whether exposure to STX could alter the susceptibility of harbor seal immune cells to PDV infection upon in-vitro exposure. STX caused an increase in harbor seal lymphocyte proliferation at 10ppb and exposure to STX significantly increased the amount of virus present in lymphocytes. These results suggest that low levels of STX within the range of those reported in northeast U.S. seals may affect the likelihood of systemic PDV infection upon in-vivo exposure in susceptible seals. Given the concurrent increase in morbillivirus epizootics and HAB events in the last 25 years, the relationship between low level toxin exposure and host susceptibility to morbillivirus needs to be further explored.

A review of the status of harbour seals ( Phoca vitulina ) in the Northeast United States of America

We conducted a review of the literature and unpublished databases to describe the distribution, abundance, ecology and status of harbour seals ( Phoca vitulina concolor ) in U.S. Atlantic waters. The harbour seal is the most abundant and widespread seal species in this area. Since passage of the U.S. Marine Mammal Protection Act of 1972, the number of harbour seals observed during the pupping season in this region has increased from about 10,500 animals in 1981 to 38,000 animals in 2001 (uncorrected counts), an average annual rate of 6.6%. This increase has been relatively consistent over the 20 years, and there is no indication that the population size has stabilized. Correspondingly, the seasonal distribution has expanded and interactions between seals and anthropogenic activities have increased.

North Atlantic Marine Mammals

Publisher Summary Marine mammals are a diverse, widespread, and significant component of North Atlantic marine ecosystems. Four of the five commonly recognized marine mammal taxa reside in the North Atlantic: cetaceans, sirenians, pinnipeds, and polar bears. A fifth taxon and sea and sea lions and fur seals (family Otariidae) have not inhabited the North Atlantic since at least the late Pleistocene. The systematics of marine mammals is still being disputed. Marine mammals occupy all North Atlantic marine regimes, tropical to polar, although species-specific ranges exist and distribution patterns are not uniform. The large-scale, nonrandom distribution of marine mammals is influenced by oceanographic features, whereas small-scale distributions are influenced by factors such as the animals physiology, behavior, and ecology. The physical characteristics of the North Atlantic ecosystem critically influence marine mammal distribution. Although the ocean basin provides marine mammals with an open pathway that extends from the equator northward to the Arctic and includes adjacent bodies of water, the North Atlantic has many different ecosystems. Some adjacent seas, such as the Baltic and Mediterranean, are more isolated from the open ocean and form separate ecosystems. Baleen whales are widely distributed in the North Atlantic, with individual species exhibiting preferences for certain ecosystems. Centuries of human activities have affected all North Atlantic marine mammal populations. Prehistoric people hunted coastal marine mammals for subsistence use, and in some areas aboriginal hunting still exists. Commercial exploitation of smaller cetaceans began in the fourteenth century when the Danes initiated organized hunts of Baltic Sea harbor porpoises.