Poster Session 2 Abstracts
Total Page:16
File Type:pdf, Size:1020Kb
Seabirds: Linking the Global Oceans Poster Session 2 Abstracts The 1st World Seabird Conference has the distinct pleasure of presenting over 700 presentations during the conference September 7 to 11, 2010 in Victoria, Canada. These presentations include over 120 Invited Sessions, over 120 Contributed Sessions, and over 380 Posters. A series of Legacy Worshops, other Workshops and a Legacy Plenary round out the conference program. This document presents the full abstracts for the Poster Sessions. Victoria Conference Centre Victoria, Canada • September 7- 11, 2010 1ST WORLD SEABIRD CONFERENCE • POSTER SESSION 2 ABSTRACTS 12 Bycatch regardless of the discharge type. Reducing the aerial extent of third-wires also reduced third-wire strike rates, but was less effective than streamer lines. Warp booms designed to divert P2-1 Kimberly Dietrich seabirds from warps failed to significantly reduce seabird Seabird bycatch in Alaska trawl fisheries: A warp strikes, but this technique can be improved. Collectively comparison of observer sampling protocols these results show for the first time that seabird strikes with ìmodernî third-wire trawl sonar cable systems can be reduced “Seabird bycatch in commercial fisheries, especially longline, through gear modification and that warp strikes can be trawl and gillnet fisheries, is recognized as a global mitigated with techniques similar those in place in southern conservation problem. In some southern hemisphere fisheries hemisphere fisheries. However, because only small-winged the bycatch of certain albatross species has been identified as birds classified as of least conservation concern were struck the cause for serious population declines. North Pacific and appeared unharmed the need for mitigation in the EBS pollock fishery is questioned.” Groundfish Observers conduct species composition sampling Kimberley Dietrich; Shannon Fitzgerald; Tamre Cordoza on trawlers to support estimation of total removals for a variety of species. Sampling protocols work well in support of estimates of mortality for most fish species. Unfortunately, the P2-3 Angel David Mac’as estimates of seabird mortalities associated with trawl fishing operations are likely biased as seabird mortalities may also Factors affecting Mediterranean Cory’s occur from encounters with rigging (trawl sonar and trawl Shearwater bycatch in Spanish longline fisheries door cables) or the net forward of the codend. Current from Mediterranean Sea sampling protocols are not able to account for either of these situations. Observers have been collecting data on seabird “Cory’s shearwater Calonectris diomedea is currently listed interactions with trawl warps, nets, and third wires over like least concern in the UICN red-list. However, the several years as part of a special project assigned to prior, subspecies C. d. diomedea is listed as Endangered. This experienced observers only. We compare seabird bycatch subespecies is the principal Seabird caught by the Spanish based on current observer protocols with the number of birds Mediterranean longline (30.7% of total seabird by-catches). caught using the specialized observation protocols. Initial For this reason, understanding factors determining seabird by- summaries reinforce the hypothesis that current estimates are catch, and how to control it, is a major goal in seabird low. We review changes incorporated into standard operating conservation biology. We performed a binary logistic procedures for observers as a result of this work and regression on the presence or absence of Cory’s shearwater recommend methods to improve seabird monitoring on by-catch and the predictive variables to test if the probability trawlers in Alaska.” of incidentally catching Cory’s shearwater (1 or more) may be Shannon Fitzgerald predicted by the combination of several phenological (27 variables), ecogeographical (5 variables) and technical factors (5 variables). Moreover we used the interaction with others WITHDRAWN P2-2 Ed Melvin fisheries. The interaction with others fisheries was estimate as Reducing seabird strikes with trawl cables in the the non-working days, because in function to Spanish Pollock Catcher-Processor Fleet in the Eastern normative the longline fleets is the only fisheries that can Bering Sea fisher in non-working days. A total of 2587 fishing operations were observed from January to December, during the years “Little is known about threats posed to seabirds by cable 2000 to 2009, which represent 5398297 hooks controlled strikes in northern hemisphere trawl fisheries or what directly, with 80 Cory’s shearwater by-caught in 30 fishing mitigation measures might reduce those threats. We compared operations. We obtained a statistically significant logistic the rate of heavy seabird strikes with third-wire (scanning model with the variables: number of hooks, sets over trawl sonar) cables and warps, using three mitigation continental shelf, October, non-working days, and distance to measures, third-wire snatch block, streamer lines, and warp the colony of Paloma Island. The model’s goodness-of fit-was booms, compared to a control of no deterrent aboard two significant (Omnibus test= 96.644, df= 6, p= 0.001; Hosmer catcher-processor vessels targeting pollock in the eastern and Lemeshow test= 10.135, df= 8, p= 0.256), and its discrimination capacity was outstanding (AUC = 0.912).” Bering Sea (EBS), one that rendered the majority of the offal Salvador García-Barcelona; José Carlos B·ez; and bycatch into fish meal and fish oil and one that Raimundo Real; Enrique Alot discharged macerated offal. More birds attended the nonmeal- vessel, but the rate of seabird cable strikes was higher for the meal-vessel, due to the greater aerial extent of its cables. Streamer lines significantly reduced heavy seabird strikes with both cable types by at least an order of magnitude 1ST WORLD SEABIRD CONFERENCE • POSTER SESSION 2 ABSTRACTS 3 P2-4 Joan Browder government have implemented measures that have been Modeling low rates of seabird bycatch in the aimed at reducing seabird bycatch. These include the U.S. Atlantic longline fishery compulsory use of streamer lines, or similar mitigation devices, on larger trawlers. While experimental work suggests “Incidental capture of seabirds in commercial fisheries is a that mitigation devices reduce seabird bycatch, the observer worldwide issue of concern for potential damage to data allows the fisheries-wide effects of mitigation usage to vulnerable populations and their ecosystems. NMFS SEFSC be assessed. Time series of capture-rates and total captures are initiated a project in 2004 to improve seabird bycatch used to determine whether the introduction of mitigation has estimation in the U.S. Atlantic pelagic longline fishery. The resulted in a decrease in the total captures.” project’s first component was training in the Pelagic Observer Finlay Thompson Program to improve the specificity and accuracy of seabird identification. The most recent component is development of WITHDRAWN P2-6 Cleo Small a new analytical approach to improve estimation of the total annual seabird bycatch of the fleet based on observer data. Reducing seabird bycatch from the top: Progress Catch, bycatch, effort, and other information are reported on in regional fisheries management organizations observed longline trips. Estimates of total annual seabird bycatch are extrapolated from observed trips to the entire fleet “Regional Fisheries Management Organizations (RFMOs) based on total effort. The infrequency of seabird bycatch in have a central role in the sustainable management of the observed longline sets (0 to 33 birds per year from 1992 to world’s oceans and the conservation of species vulnerable to 2008 in ~5500-17300 observed sets) and low proportions of bycatch. The Commission for the Conservation of Antarctic sets observed (2-7% from 1992 to 2005 and 10-14% from Marine Living Resources (CCAMLR) has demonstrated what 2006 to 2008), raised concerns about reliability of estimates, can be achieved, hvaing reduced seabird bycatch by over 99% leading to this work. We examined alternate methods of in its regulated fisheries around South Georgia. However the estimating seabird bycatch using generalized additive models world’s five tuna commissions overlap with more than 80% of (GAM), generalized linear models (GLM), and GLM with the world’s albatross and petrel distribution. In 2004, only one spatially auto-correlated parameters. Models were applied tuna commission had requirements for seabird bycatch separately to probability of seabird bycatch mitigation by its longline fleets. We review progress achieved (presence/absence) and numbers of seabirds per positive between 2005-2010 through collaboration between member bycatch; then multiplied. AIC suggested best-fitting models states, ACAP and other stakeholders, and identify future included latitude, longitude, and quarter of year for challenges.” presence/absence and numbers of hooks per set for positive bycatch. A composite model of GAM (presence/absence) and P2-7 Lewis Van Fossen GLM (positive catch) gave best predictions of total seabird Seabird mitigation measures in Hawaiian bycatch.” Andreas Winter; Yan Jiao longline fisheries “The U.S. National Marine Fisheries Service’s Pacific Islands P2-5 Edward Abraham Regional Office (PIRO) annually issues reports detailing Seabird bycatch in New Zealand fisheries seabird interactions for its pelagic longline fisheries. These reports can be accessed on the PIRO web site at: “New Zealand has a rich seabird