NRRM 200 Statistics on Bycatch's Effects on Marine Mammals Slideshow.pdf
- 1. BYCATCH AND ITS EFFECTS ON MARINE MAMMAL POPULATIONS Student: RowanSales Date: 9/20/2017 Class: NRRM 200
- 3. BASICS OF BYCATCH A tactic used by the fishing industry, bycatch is when marine species, both ones that are utilized as seafood and others that are not, are caught not intentionally while searching for organisms to collect – which has been used since the 1970s and its devastating effects can be felt on the marine mammal population (Reevees, et al., 2013). The two most common examples include shrimp trawling and recreational fishing. Over the past few decades, this new trend known as bycatch has been decimating populations of marine mammals in the thousands due to trends of increased human population and a higher demand for the sea food. (Read et al. 2005). Marine mammals that are caught in bycatch often have been injured and killed –This has even led to the extinction of some species of marine mammals. (Read, 2008).
- 5. “BYCATCH OF MARINE MAMMALS IN U.S. AND GLOBAL FISHERIES” Throughout the 90’s, a collaboration between Duke University in North Carolina and the University of St. Andrews in the United Kingdom was set up to study how marine mammal populations was effected by the implementation of bycatch. The study was conducted byAndrew J. Read, Phebe Drinker, and Simon Northridge. Their goal was to study how the populations of marine mammals, cetaceans and pinnipeds was being demolished by the fishing industry.
- 6. THE AIM OFTHE STUDY The study focused on three regions of North America waters:Alaska, the Atlantic Ocean and the Pacific Ocean.This served as a global estimation of the amount of bycatch that was going on in the oceans of the world. The questions asked included questions such as what the current level of bycatch was and what the bycatch rate was for pinnipeds and cetaceans who happened to get caught up in the fishing vessels. The four hypotheses that were stated by the scientists were the following: The amount of bycatch of marine mammals was in the thousands. The bycatch was doing damage to marine mammal populations. Pinnipeds were more likely to fall victim when compared to cetaceans. Marine mammal populations inAlaskan waters would be effected more than the Pacific Ocean and Atlantic Ocean.
- 7. METHODS IMPLEMENTED The data was collected over a period of an entire decade (1990-1999). During the trials of the experiment, they used an ANOVA, which collects the statistical data used to observe and scan the noticeable differences in a group’s means and the procedures they are associated with. Researches also looked at variance, in which they divided for the taxonomic group of marine mammals, region, and fishery type with the aid of standard errors. After that, they observed the three regions in an attempt to reduce the amount of bycatch.There were two sets of variables used for the global bycatch. For the first, the independent variable was the fishery type, and the dependent variable was the global vessels. For the second, the dependent variable was the marine mammals and the independent variable was the type of gear that was used for the bycatch. While on the subject of the NOAA, a report titled “Annual Human Caused Mortality and Serious Injury,” which was organized by the year and the fishery involved.
- 8. THE RESULTS Their results document the following information: There was a similar amount of bycatch between pinnipeds and cetaceans. Dolphins and porpoises made up a large portion of the cetaceans who fell victim to the bycatch. However, it should be noted that large baleen whales were victims of the bycatch as well, but they weren’t as common as dolphins and porpoises, at 84 percent. Seals and sea lions made up the majority of pinnipeds of that fell victim to bycatch at 98 percent. There was a negative trend with the bycatch of cetaceans. The Pacific Ocean had the highest number of causalities, followed by the AtlanticOcean while Alaska, surprisingly, had the lowest amount of causalities. Of the three types of bycatch examined in this study, the researchers found that gill-net was the most used method of bycatch, with the largest number of marine mammals being caught in it being 808,283 of them.
- 9. TABLE 1: ESTIMATESOF MARINE MAMMAL BYCATCH IN U.S. FISHERIES STRATIFIED BYTAXONAND FISHERYTYPE. Taxon and fishery type 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 Cetaceans gill net 4902 3154 2373 2489 2928 2261 2624 2095 1481 1051 trawl 195 297 232 133 199 195 999 436 116 332 other 3 9 256 60 388 475 114 11 70 408 Pinnipeds gill net 1921 3312 5626 3573 3540 3136 2472 2873 2323 2344 trawl 19 36 34 10 29 3 15 17 14 11 other 151 149 148 10 29 30 6 20 15 0
- 10. TABLE 2: ESTIMATES OF MARINE MAMMAL BYCATCH INU.S. FISHERIES, STRATIFIED BYTAXONAND REGION Year Atlantic Pacific Alaska cetaceans pinnipeds total cetaceans pinnipeds total cetaceans pinnipeds total 1990 4574 602 5176 451 1363 1814 76 126 202 1991 2696 231 2927 705 3143 3848 60 123 183 1992 2192 373 2565 639 5340 5979 31 95 126 1993 2142 716 2858 521 2740 3261 20 137 157 1994 3153 2210 5363 342 1332 1674 21 31 52 1995 2419 2018 4437 489 1118 1607 23 33 56 1996 3214 1049 4263 506 1432 1938 18 12 30 1997 2208 998 3206 313 1897 2210 22 15 37 1998 1523 499 2022 124 1840 1964 21 13 34 1999 1649 1682 3331 133 662 795 9 11 20
- 11. TABLE 3. ESTIMATES OF BYCATCH OF MARINE MAMMALS INTHE WORLD'S FISHERIES (NUMBEROFVESSELSUSEDTO EXPAND U.S. ESTIMATESTO GLOBALTOTALS). Fishery type and year No. of U.S. vessels Total no. of vessels Global cetacean bycatch Global pinniped bycatch Global marine mammal bycatch Gill net 1990 2,140 203,598 466,392 182,763 649,154 1991 2,140 217,585 320,633 336,748 657,381 1992 2,160 218,272 239,766 568,518 808,283 1993 2,500 219,461 218,513 313,654 532,167 1994 2,500 220,500 258,250 312,228 570,478
- 12. TABLE 3. ESTIMATES OF BYCATCH OF MARINE MAMMALS INTHE WORLD'S FISHERIES (NUMBEROFVESSELSUSEDTO EXPAND U.S. ESTIMATESTO GLOBALTOTALS)… CONT. Trawl 1990 7,446 129,403 3,389 330 3,719 1991 7,440 130,128 5,198 630 5,828 1992 8,150 132,957 3,790 555 4,344 1993 8,290 137,720 2,213 166 2,379 1994 8,030 137,479 3,407 496 3,904 Fishery type and year No. of U.S. vessels Total no. of vessels Global cetacean bycatch Global pinniped bycatch Global marine mammal bycatch
- 13. TABLE 3. ESTIMATES OF BYCATCH OF MARINE MAMMALS INTHE WORLD'S FISHERIES (NUMBER OFVESSELSUSEDTO EXPAND U.S. ESTIMATESTO GLOBALTOTALS)… CONT. Fishery type and year No. of U.S. vessels Total no. of vessels Global cetacean bycatch Global pinniped bycatch Global marine mammal bycatch Other 1990 3,220 77,640 72 3,645 3,717 1991 3,180 79,045 222 3,708 3,930 1992 3,230 80,606 6,382 3,698 10,079 1993 3,495 80,366 1,377 235 1,612 1994 3,430 80,991 9,164 685 9,849
- 14. A DISCUSSION With climate change warming the oceans, it could and will kill off many species of organisms and will also likely result in populations of organisms getting smaller and smaller. Coupling that idea above with a massive amount of pollution taking place, it is sad to say that the future of our oceans doesn’t look to bright. However, not all hope is lost – as there are people who do studies like this… people who care.
- 15. REFERENCES 1. Barlow, J., & Cameron, G. A. (2003). Field Experiments ShowThat Acoustic Pingers Reduce Marine Mammal Bycatch InThe California Drift Gill Net Fishery. Marine Mammal Science, 19(2), 265-283. doi:10.1111/j.1748-7692.2003.tb01108.x 2. NOAA Fisheries. (2015, May 07). Bycatch Explained. Retrieved September 11, 2017, from http://www.nmfs.noaa.gov/stories/2015/05/05_07_15whatisbycatch.html 3. Read, A. J., Drinker, P., & Northridge, S. (2006). Bycatch of Marine Mammals inU.S. and Global Fisheries. Conservation Biology, 20(1), 163-169. doi:10.1111/j.1523-1739.2006.00338.x 4. Read, A. J. (2008). The looming crisis: interactions between marine mammals and fisheries. Journal of Mammalogy, 89(3), 541-548. doi:10.1644/07-mamm-s-315r1.1 5. Reeves, R., Mcclellan, K., & Werner, T. (2013). Marine mammal bycatch in gillnet and other entangling net fisheries, 1990 to 2011. Endangered Species Research, 20(1), 71-97. doi:10.3354/esr00481