Physical Sciences and Mathematics Commons^™

Trends In Catch Rates Of Sawfish On The Australian North West Shelf, C. Wakefield, S. J. Newman, M. Braccini, A. Harry

Fisheries Research Articles

Northwestern Australia is thought to have some of the world’s last remaining viable sawfish populations, although little quantitative data exists on their status or trends. This study examined 17 years of logbook bycatch records (n = 815) for green sawfish Pristis zijsron and narrow sawfish Anoxypristis cuspidata from a trawl fishery operating on the Australian North West Shelf. Incidental sawfish captures by the fishery are rare, occurring approximately once every 75 trawls (~199 trawl hours). To standardize catch rates and account for excess zeros in the data, we employed generalized additive models for location, scale, and shape (GAMLSSs) using a …

First Estimates Of Greenland Shark (Somniosus Microcephalus) Abundances In Arctic Waters, Taryn Szalay

Scientific Communication News

No abstract provided.

Analysis Of "Observer Effect" In Logbook Reporting Accuracy For U.S. Pelagic Longline Fishing Vessels In The Atlantic And Gulf Of Mexico, Thomas J. Morrell

HCNSO Student Theses and Dissertations

Commercial pelagic longline fishers within the U.S. Atlantic, Gulf of Mexico, and Caribbean are required to report all fishing interactions per each gear deployment to NOAA’s Vessel Logbook Program of the Southeast Fisheries Science Center to quantify bycatch, increase conservation efforts, and avoid jeopardizing the existence of vulnerable species listed under the Endangered Species Act (ESA). To provide additional accuracy, the Pelagic Observer Program (POP) of the SEFSC deploys professionally trained observers on longline vessels to produce a statistically reliable subset of longline fisheries data. A comparison of self-reported (“unobserved”) datasets versus observer-collected (“observed”) datasets showed a general consistency for …

Vaquita Face Extinction From Bycatch. Comment On Manjarrez-Bringas, N. Et Al., Lessons For Sustainable Development: Marine Mammal Conservation Policies And Its Social And Economic Effects., Karl W. Flessa, Luis Calderon-Aguilera, Carlos E. Cintra-Buenrostro, David L. Dettman, Gregory P. Dietl, David H. Goodwin, David K. Jacobs, Michal Kowalewski, Steven M. Nelson, Kirsten Rowell, Bernard R. Schone, Jansen A. Smith, Francisco Zamora-Arroyo

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

We are among the scientists who have documented the environmental and ecological changes to the Upper Gulf of California following the reduction in the Colorado River’s flow. We object to any suggestion that our research supports Manjarrez-Bringas et al.’s conclusion that the decline in the Colorado River’s flow is the reason for the decline in the population of the endangered vaquita porpoise (Phocoena sinus). Manjarrez-Bringas et al.’s conclusions are incongruent with their own data, their logic is untenable, their analyses fail to consider current illegal fishing practices, and their recommendations are unjustified and misdirected. Vaquita face extinction because of bycatch, …

Spatio-Temporal Dynamics Of Atlantic Cod Bycatch In The Maine Lobster Fishery And Its Impacts On Stock Assessment, Robert E. Boenish

Electronic Theses and Dissertations

Of the most iconic fish species in the world, the Atlantic cod (Gadus morhua, hereafter, cod) has been a mainstay in the North Atlantic for centuries. While many global fish stocks have received increased pressure with the advent of new, more efficient fishing technology in the mid-20^th century, exceptional pressure has been placed on this prized gadoid. Bycatch, or the unintended catch of organisms, is one of the biggest global fisheries issues. Directly resulting from the failed recovery of cod in the GoM, attention has been placed as to possible sources of unaccounted catch. Among the most …

Fishery Interaction Modeling Of Cetacean Bycatch In The California Drift Gillnet Fishery To Inform A Dynamic Ocean Management Tool, Nicholas B. Sisson

Biological Sciences Theses & Dissertations

Understanding the drivers that lead to interaction between target species in a fishery and marine mammals is a critical aspect in efforts to reduce bycatch. In the California drift gillnet fishery static management approaches and gear changes have reduced bycatch but neither measure ascertains the underlying dynamics causing bycatch events. To avoid further potentially drastic measures such as hard caps, dynamic management approaches that consider the scales relevant to physical dynamics, animal movement and human use could be implemented. A key component to this approach is determining the factors that lead to fisheries interactions. Using 25 years (1990-2014) of National …

Sea Turtles And Survivability In Demersal Trawl Fisheries: Do Comatose Olive Ridley Sea Turtles Survive Post-Release?, Sara M. Maxwell, Matthew J. Witt, Gaspard Abitsi, Marie Pierre Aboro, Pierre Didier Agamboue, Georges Mba Asseko, Francois Boussamba, Emmanuel Chartain, Micheline Schummer Gnandji, Brice Didier Koumba Mabert

Biological Sciences Faculty Publications

Incidental capture of air‑breathing species in fishing gear is a major source of mortality for many threatened populations. Even when individuals are discarded alive, they may not survive due to direct injury, or due to more cryptic internal physiological injury such as decompression sickness. Post‑release mortality, however, can be difficult to determine. In this pilot study, we deployed survivorship pop‑up archival tags (sPAT) (n = 3) for an air‑breathing species, the olive ridley sea turtle (Lepidochelys olivacea), one of the first studies to do so. We found that at least two of the three turtles survived after being …

Informing Marine Protected Area Designation And Management For Nesting Olive Ridley Sea Turtles Using Satellite Tracking, Tiffany M. Dawson, Angela Formia, Pierre D. Agamboué, Georges M. Asseko, François Boussamba, Floriane Cardiec, Emmanuel Chartrain, Philip D. Doherty, J. Michael Fay, Brendan J. Godley, Francis Lambert, Brice D. Koumba Mabert, Jean C. Manfoumbi, Kristian Metcalfe, Gianna Minton, Ivan Ndanga, Jacob Nzegoue, Carmen K. Kouerey Oliwina, Philippe Du Plessis, Guy-Philippe Sounguet, Dominic Tilley, Matthew J. Witt, Sara M. Maxwell

Biological Sciences Faculty Publications

Understanding the horizontal and vertical habitat of olive ridley sea turtles (Lepidochelys olivacea), a threatened species, is critical for determining regions for protection and relevant gear modifications that may effectively reduce bycatch, the largest threat to this species. Satellite transmitters were used to determine the movement and dive behavior of 21 female olive ridley turtles tagged in Pongara National Park, Gabon during the 2012, 2013, and 2015 nesting seasons. A switching state-space model was used to filter the tracking data and categorize the internesting and post-nesting movements. Gridded utilization distribution (UD) home range analysis of tracking data revealed …

Dynamic Ocean Management Increases The Efficiency And Efficacy Of Fisheries Management, Daniel C. Dunn, Sara M. Maxwell, Andre M. Boustany, Patrick N. Halpin

Biological Sciences Faculty Publications

In response to the inherent dynamic nature of the oceans and continuing difficulty in managing ecosystem impacts of fisheries, interest in the concept of dynamic ocean management, or real-time management of ocean resources, has accelerated in the last several years. However, scientists have yet to quantitatively assess the efficiency of dynamic management over static management. Of particular interest is how scale influences effectiveness, both in terms of how it reflects underlying ecological processes and how this relates to potential efficiency gains. Here, we address the empirical evidence gap and further the ecological theory underpinning dynamic management. We illustrate, through the …

Interactions Between Short-Beaked Common Dolphin (Delphinus Delphis) And The Winter Pelagic Pair-Trawl Fishery Ff Southwest England (Uk), Marijke N. De Boer, James T. Saulino, Mardik F. Leopold, Peter J.H. Reijnders, Mark P. Simmonds

Mark P. Simmonds, OBE

During offshore and onshore studies (2004 to 2009), the interactions between pair-trawls and short-beaked common dolphins (Delphinus delphis) were studied to better understand the impact of bycatch. A ‘hotspot’ area where pair-trawls overlapped with high dolphin abundance was identified. We made comparisons between boat-based data collected in absence and presence of pair-trawlers. The relative abundance and group-size of dolphins was significantly higher in the presence of pair-trawlers. Dolphins were observed associating with towing and hauling procedures. Significantly, more carcasses occurred in areas with hauling-activity than those without. Body-temperatures obtained from carcasses found near operating pair-trawlers indicated that bycatch mostly occurred …

What’S The Catch? Patterns Of Cetacean Bycatch And Depredation In Hawaii-Based Pelagic Longline Fisheries, Karin A. Forney, Donald R. Kobayashi, David W. Johnston, Jamie A. Marchetti, Michael G. Marsik

United States Department of Commerce: Staff Publications

U.S. Pacific pelagic longline fisheries operating in the central North Pacific have been subject to a series of regulations to reduce bycatch of protected species, including seabirds and sea turtles. Cetaceans are also occasionally caught, and the bycatch of false killer whales, Pseudorca crassidens, in the Hawaii-based deep-set longline fishery currently exceeds allowable levels under the Marine Mammal Protection Act (MMPA). In this study, we examined longline observer data collected between 1994 and 2009, with emphasis on 2003–2009, to identify patterns of cetacean bycatch and depredation in relation to area, time, vessel, habitat variables, fishing gear, and set characteristics. …

Small-Scale Fisheries Of Peru: A Major Sink For Marine Turtles In The Pacific, Joanna Alfaro-Shigueto, Jeffrey C. Mangel, Francisco Bernedo, Peter H. Dutton, Jeffrey A. Seminoff, Brendan J. Godley

United States Department of Commerce: Staff Publications

1. Over the last few decades, evidence of marine vertebrate bycatch has been collected for a range of industrial fisheries. It has recently been acknowledged that large impacts may also result from similar interactions with small-scale fisheries (SSF) due largely to their diffuse effort and large number of vessels in operation. Marine mammals, seabirds, turtles as well as some shark species have been reported as being impacted by SSF worldwide.

2. From 2000 to 2007, we used both shore-based and onboard observer programmes from three SSF ports in Peru to assess the impact on marine turtles of small-scale longline, bottom …

A Bycatch Action Plan For The Pilbara Fish Trawl Interim Managed Fishery., Department Of Fisheries Western Australia

Fisheries management papers

The effect of commercial fishing on bycatch species and the marine ecosystem generally, has emerged as a significant national and international issue. Environmental issues associated with bycatch – including impacts on the ecology of non-target species of fish and wildlife – are important issues to address in reducing the impacts, or potential impacts, of commercial fisheries.

In 1998, the National Standing Committee on Fisheries and Aquaculture developed a national policy on fisheries bycatch. In 1999, the (then) State Minister for Fisheries adopted the national policy as his position on bycatch for Western Australia. The main objective of the policy is …

Fisheries Research Report No. 171 - Evaluation Of Exclusion Grids To Reduce The Bycatch Of Dolphins, Turtles, Sharks And Rays In The Pilbara Trawl Fishery, Peter Stephenson, S. Wells, J. A. King

Fisheries research reports

DBIF funded Project.

Considerable research on the documention of the bycatch of cetaceans, seals, turtles, and sea lions during trawl fishing operations has been undertaken worldwide. These include the Argentinean squid and hake trawl fisheries (Crespo et al., 1997; Fertl & Leatherwood, 1997), the Dutch pelagic trawl fishery (Couperus, 1997), the NE Atlantic pelagic trawl fishery (Tregenza & Collet, 1998) and the New Zealand squid fishery (Fishing News International, 2005).

In the Pilbara Fish Trawl Fishery, operating off the coast of Western Australia protected species including dolphins, turtles, sawfish, sea snakes as well as numerous sharks and ray species have …

Fisheries Research Report No. 160 - Development Of Biodiversity And Habitat Monitoring Systems For Key Trawl Fisheries In Western Australia., Mervi Kangas, S. Morrison, P. Unsworth, Eva K M Lai, I. Wright, Adrian W. Thomson

Fisheries research reports

Final FRDC report - Project 2002/038

The need for this project was identified through the ESD Risk Assessment workshops held for the Shark Bay and Exmouth Gulf trawl fisheries in May and October 2001. Bycatch issues in the Shark Bay and Exmouth fisheries were identified as a moderate risk through an Ecological Risk Assessment workshop. A better understanding of the faunal composition and habitat preferences of bycatch species in both trawled and untrawled areas has assisted in determining the level of risk to bycatch species. The project provided baseline data on biodiversity and variability of trawl bycatch on and off …

Western Rock Lobster Fishery - Ecological Risk Assessment 2005 Report., Mark Burgman

Fisheries management papers

The first two parts of the document provide background on the western rock lobster fishery and its governance. The third and fourth parts outline reporting requirements for the Ecologically Sustainable Development process and the specifics of the risk assessment process applied here. These sections are based substantially on reports written earlier by the Department of Fisheries and distributed to participants in the risk assessment process. They have been edited here to include only the details that were pertinent to this risk assessment. Parts 5, 6 and 7 provide the outcomes of the hazard elicitation workshop with stakeholders and the subsequent …

Fisheries Research Report No. 148 - Historical Distribution And Abundance Of The Australian Sea Lion (Neophoca Cinerea) On The West Coast Of Western Australia, Richard Campbell

Fisheries research reports

Analysis of historical patterns of abundance of the Australian sea lion on the west coast of Western Australia suggests that the population size was greater prior to the impacts of colonization and commercial sealing/whaling between the 18th and 20th centuries. In addition, it is evident that there has been a reduction in the number of breeding sites along the west coast, particularly around the greater Perth metropolitan area. There is limited evidence of the impact of indigenous hunting on the abundance and distribution of this species. The major impacts on Australian sea lion populations were a combination of subsistence and …

Field Experiments Show That Acoustic Pingers Reduce Marine Mammal Bycatch In The California Drift Gill Net Fishery, Jay Barlow, Grant A. Cameron

United States Department of Commerce: Staff Publications

A controlled experiment was carried out in 19961997 to determine whether acoustic deterrent devices (pingers) reduce marine mammal bycatch in the California drift gill net fishery for swordfish and sharks. Using Fisher’s exact test, bycatch rates with pingers were significantly less for all cetacean species combined (P < 0.001) and for all pinniped species combined (P = 0.003). For species tested separately with this test, bycatch reduction was statistically significant for shortbeaked common dolphins (P = 0.001) and California sea lions (P = 0.02). Bycatch reduction is not statistically significant for the other species tested separately, but sample sizes and statistical power were low, and bycatch rates were lower in pingered nets for six of the eight other cetacean and pinniped species. A log-linear model relating the mean rate of entanglement to the number of pingers deployed was fit to the data for three groups: short-beaked common dolphins, other cetaceans, and pinnipeds. For a net with 40 pingers, the models predict approximately a 12- fold decrease in entanglement for short-beaked common dolphins, a 4-fold decrease for other cetaceans, and a 3-fold decrease for pinnipeds. No other variables were found that could explain this effect. The pinger experiment ended when regulations were enacted to make pingers mandatory in this fishery.