Ecosystem-Based Management of Pacific herring (Clupea pallasii) and Pink salmon (Oncorhynchus gorbusha) in Prince William Sound

Transcription

1 Ecosystem-Based Management of Pacific herring (Clupea pallasii) and Pink salmon (Oncorhynchus gorbusha) in Prince William Sound Tiger Sharks: Shayla Jordan* Christopher Erickson Aspen Melton Jake Carlton Tess Adams Mat-Su Career and Technical High School 2472 N. Seward Meridian Pkwy Wasilla, AK Phone: (907) * Team Contact: shayla.jordan86@gmail.com Coach: Timothy Lundt Timothy.Lundt@matsuk12.us

2 Abstract Prince William Sound, located between the Kenai Peninsula and the city of Cordova, is an extensive ecosystem requiring proper management to flourish. Of its many species, this paper focuses on the following three: Pacific herring (Clupea pallasii), Pink salmon (Oncorhynchus gorbusha), and the Salmon shark (Lamna ditropis). Pacific herring and Pink salmon populations rapidly declined in 1989 due to the Exxon Valdez oil spill, resulting in the annulment of the Pacific herring fishery. In the years following the spill, it became evident that the population was beginning to recover, but the unexpected low return in 1993 devastated the population. In the Pacific herring fishery was briefly reopened, but was closed in 1999 due to the low return numbers, which was contributed to stress on the already struggling population. The population has not since recovered. Many factors have been hypothesized, including disease, genetic defects, increased Polycyclic Aromatic Hydrocarbon (PAH) levels contributed to marine pollution, increased competition and predation by Pink salmon released by the Prince William Sound Aquaculture Corporation (PWSAC) hatcheries, as well as impacts of the Salmon shark on Pink salmon and Pacific herring. We discuss and propose management solutions for each hypothesis with an emphasis on increased predation and competition with PWSAC Pink salmon hatcheries and increased PAH levels contributed to marine pollution. We propose the founding of an Advisory Committee to discuss and provide recommendations to the Alaska Board of Fisheries and the Alaska Department of Fish and Game concerning the proposed Pacific herring hatcheries, PAH water testing, and proposed bycatch solutions to provide an ecosystem-based management approach to Pink salmon and Pacific herring management in the Prince William Sound. 2

3 Introduction Prince William Sound, in the northwest extent of the Gulf of Alaska, is characterized by its convoluted coast made of many islands and fjords containing tidewater glaciers. Three principal barrier islands: Montague Island, Hinchinbrook Island, and Hawkins Island enclose and define the Prince William Sound (Crestin 2002). (Figure 1) The Copper River Delta covers over 700,000 acres of land and stretches along 65 miles of the Alaskan Coast. Eighteen percent of the Copper River watershed is glaciated, contributing to the 69 million tons of sediment per year deposited at the Copper River Delta (Cline 2005). The Delta, which is made up of a mixture of brackish, salt, and freshwater, is characterized by various marshes, lakes, ponds, wetlands, and streams that range in depth from 35 to 45 inches (Cline 2005). The Alaska Coastal Current (ACC) is driven northwestward along the Canadian Coast, into the Gulf of Alaska, and down the Aleutian Chain by the along-shore winds and freshwater discharge around the coastal regions of the Gulf of Alaska (GOA) (Mundy 2005). The coastal downwelling system of the GOA extends over 1,500 km along the Alaskan Coast and largely contributes to the nutrient base that circulates from the Copper River Delta through Prince William Sound (Stabeno et. al 2004). (Figure 2) This nutrient base upwells plankton, the primary food source for Pacific herring (Clupea pallasii) and enriches the abundant marine life that calls it home (Buckhorn 2011). 3

4 Pacific Herring Pacific herring (Clupea pallasii) are a schooling fish species that represent a fair portion of the gross economical revenue of Alaskan fisheries and are of high value to subsistence fishers because of their availability (Buckhorn 2011). Pacific herring start their life buried in the thick grass of intertidal and shallow sub-tidal waters of the coastline between the months of October and July, and peak during February and March (Lassuy 1989). The newly fertilized eggs (attached to the vegetation) usually take about 2-3 weeks to incubate before hatching. The Herring then undergo metamorphosis, a profound change from one life stage to the next (Collins English Dictionary 2011), 2-3 months after hatching and reach average lengths of mm. During the first summer of their lives they begin to gather into a school, and move offshore to depths of meters (National Marine Fisheries Service). Pacific herring will begin eating both phytoplankton and zooplankton when they reach a length of mm (Pacific herring Clupea Pallasii 1989). Their diet primarily consists of copepods, diatoms, as well as the larva and eggs of various planktonic organisms (Lassuy 1989). By the time the herring undergo metamorphosis, they begin eating barnacles and mollusk larvae, a variety of zooplankton, and larval fish in addition to their main staple of copepods. As they continue to mature, herring will begin to include amphipods and decapod larvae in their diet, and copepods may be superseded by euphasids. Pacific herring usually reach first maturity in 3-4 years after hatching (Alaska Department of Fish and Game 2011). After reaching sexual maturity the herring return every year to spawn at the same general spawning area. 4

5 Pink Salmon During the months of July through October, female Pink salmon will typically produce up to 4,300 eggs for fertilization, but up to eighty-five percent of these eggs will be lost before hatching due to dissolved oxygen level fluctuation, freezing, pollution, and predation (Hakanson 2010). A newly hatched salmon is called an alevin. In this stage it feeds from the yolk sac attached to its stomach. Once the sac has been absorbed, the pink salmon begins to move down stream to begin the transition from freshwater to saltwater. Once the transition is complete, the salmon will spend 18 months in the ocean as a smolt (juvenile salmon), where they will become a spawning adult after two years. When they are ready to spawn they return to their natal stream and males develop a hump and red stripes on their sides. Normally developed adult pink salmon (Onchyronchus gorbusha) weigh an average 3.5 to 5 pounds and are on average inches in length, making them the smallest salmon harvested in Alaska (Fairbanks Fish and Wildlife Field Office 2009). They are usually found near the shores of Prince William Sound. These salmon also have the shortest lifespan of all the Pacific salmon with only two years. This short life span has caused the fish to mate in odd and even years (Fairbanks Fish and Wildlife Field Office 2009). Pink salmon are the most abundant salmon in North America. Between the years of 1959 and 1992, 45.1 million salmon were harvested annually, but in 1997 to 2006 the annual harvest rose to 107 million pink salmon (an annual increase of 61.9). Sport fishing from 1996 to 2006 harvested an annual 154,600 pink salmon (Alaska Department of Fish and Game 2011). 5

6 Salmon Shark The salmon shark (Lamna ditropis) is one of the warmest of all Pacific sharks, maintaining a consistent temperature of 8-12 degrees Celsius above water temperature at an average depth of 152 meters deep (Alaska Department of Fish and Game 2011). This causes the salmon shark to live an extensive predatory life. Salmon sharks usually hunt in groups; as many as 40 sharks in the Prince William Sound may follow a single school of herring at any given time. Many commercial fishermen in the Prince William Sound consider this shark a nuisance and a competitor. Every year the salmon shark populations consume 12 to 25 percent of the annual salmon run (Aidan 2003). Due to the negative views of the salmon shark, fishermen are encouraged to add to its mortality rate by sport fishing. Adding to the distress of the low population, the salmon shark s low reproduction rates (4-5 pups every two years) puts the population at risk for permanent suppression (Roman). Salmon sharks usually mate in the late summer early autumn and will typically give birth in the spring. These sharks have a gestation period of nine months and may give births up to 5 pups at one time. Male salmon sharks will bite the female while mating to hold them still during fertilization. Pups are born anywhere from 2 to 3 feet in length and may grow up to 10 feet long. Salmon shark populations are slowly decreasing due to overfishing, predation during the juvenile stages. This shark is an important contribution the Prince William Sound ecosystem and if overfishing of the salmon shark is not stopped, Prince William Sound may risk losing this vital species (McNair 1993). 6

7 The Prince William Sound Fishery The commercial importance of the Prince William Sound started in the early 1890 s for fur trapping, copper mining, and fishing. From the fishing industry exploded due to the high demand of salmon and herring (Kron 2009). The Pacific herring population was rapidly declining due to over-fishing, but remained a chief export unitl the 1950 s. Pre-1989 the Pacific herring fishery in Prince William Sound brought an estimated value of $7 million (Kron 2009). The 1989 Exxon Valdez oil spill devastated the Pacific herring pouplation in the Prince William Sound and the fishery was closed. The population began to recover until 1993, when the spawning return numbers were much lower than expected. The fishery reopened in 1997 and 1998, was closed once more in The 1999 low return was later contributed to stress on the already struggling population (Cedre 2011). The Prince William Sound herring fishery has been closed and has not recovered since. (Figure 3) On December 30, 1974 the Prince William Sound Aquaculture Corporation (PWSAC) was incorporated as a nonprofit corporation to protect the fisheries from weaknesses during the wild salmon returns. By the 1970 s the salmon populations were significantly decreasing, which led to the opening of the Armin F. Koering hatchery in 1975 at Sawmill Bay, Evans Island (Kawana 1999). The PWSAC opened four additional hatcheries; the Wally Neorenberg Hatchery, the Cannery Creek Hatchery, the Main Bay Hatchery, and the Gulkana Hatchery; between the years of 1985 and 1993 (Cedre 2011). The pink salmon population also decreased in 1989, but the recovery was much quicker and less perminant. The pink salmon population increased dramatically and brought in $230 million from (Alaska Department of Fish and Game 2011). 7

8 Anthropogenic Effects The Prince William Sound is a major support system for the area s three principal ports: Whittier, Valdez, and Cordova. Marine debris and other contaminants introduced by anthropogenic sources are the current major stressors on the ecosystem s health and ability to resist and recover from change. The lack of clean and safe boating practice from fisherman is the major cause of the contaminants (Buckhorn 2011). Effects of the Exxon Valdez oil spill on Pacific herring (Clupea pallasii) and Pink salmon (Oncorhynchus gorbushca) On March 24, 1989 Exxon Valdez, an oil tanker transporting 180,000 tons of crude oil from Port Valdez to Long Beach, California, struck the Bligh Reef at a speed of 12 knots approximately 25 miles south of Valdez. The wreck damaged 11 of 18 tanks and spilled 38,500 tons of crude oil into the Valdez Arm (Cedre 2011). Crude oil contains several polycyclic aromatic hydrocarbons, which are extremely toxic when chronically exposed to fish. In samples taken three weeks after the oil spill, adult herring exhibited multifocal hepatic nectrosis (multiple localized areas of pathologic death of cells within, or portions of, the liver (Mouse Genome Database 2011)) and increased concentrations of polycyclic aromatic hydrocarbons. An experiment led by Mark Carls (1997) six years after the oil spill observed and documented the extreme biologically sublethal reproductive implications enflicted on herring larvae from the oil spill. Average Pacific herring larvae have a straight spine, a yolk sac about 3 mm long (Westernhagen) a normal jaw, and an average pericardium. 8

9 Pacific herring exposed to low levels of crude oil exhibited moderate physical mutations such as yolk edema. The defects were, however, significantly more extreme in herring exposed to high levels of crude oil. These larvae exhibited jaw deformities, pericardial edema, yolk edema, and a curved spine (Carls 1997). (Figure 4) The possibility of long-term genetic deformities was experimented upon, and though nearly all genetically damaged larvae died before metamorphosis, some diseases were still present in the 1989 spawn year, which was also detected in the 1993 return year (Carls 1997). Among the diseases was viral hemorrhagic septicemia (VHSV), which left multiple lesions in the liver of the herring. The Exxon Valdez oil spill effects on Prince William Sound pink salmon caused a rapid decline in population; however, the recovery of the population, noted in Figure 5, leads us to believe that it is not a significant threat to the population (Neff 1999). Present Management The present management for Pacific herring (Culpea pallasii) in Prince William Sound is based around the total spawning biomass in tons. The current management allows 0-20 percent of the total spawning biomass to be harvested by commercial fishing vessels with a minimum spawning escapement of 22,000 tons and a maximum of 42,500 tons (Fried). From , the pink salmon fishery was supported solely by wild stocks. The average catch in the Prince William Sound was 3.3 million, with a range of 0.1 to 7.3 million (Eggers et al. 1991). Since the beginning of the hatcheries, the average catch rose to 19.7 million with a range of 2.9 to 50.8 million; however, this massive increase is not contributed to the 9

10 hatcheries alone. The wild salmon stocks increased as the hatcheries began releasing juvenile fish. (Figure 6) Pink salmon are the least valuable of the salmon species in Alaska, but made about $170 million in the 2011 season. (Figure 7) Pink salmon commercial fishing has a catch limit based on the return spawning biomass which is changed each year (Alaska Department of Fish and Game 2011); however, sport and subsistence fishing have a limit of 6 per day per person (Alaska Department of Fish and Game 2011). Since Salmon shark fishing in Prince William Sound is strictly sport fishing, the regulations allow up to one shark per day, and two sharks per year. (Steffen 2002) Even since the steady decline in population, the regulations have not changed much. Migration may be causing the sharks to pool somewhere else during the salmon runs to feed, which is why we are not alarmed by the decrease in population within the Prince William Sound area. Proposed Management The State of Alaska holds a total aromatic hydrocarbon (AH) standard of 10 parts per billion (ppb). Water samples taken from the water column three weeks after the oil spill contained between 0.01 and 0.1 ppb; however, water surface samples contained between 10 and 29.3 ppb total aromatic hydrocarbons (Neff 1999). We propose water testing near the three major Prince William Sound islands as well as Valdez, Cordova, and Whittier to monitor salinity, dissolved oxygen, and aromatic hydrocarbons. The purpose of this testing is to monitor and improve the current water quality and condition in order to restore the Pacific herring population. The results gained from this testing can be used to identify whether oil remnants are still effecting the Prince William Sound Herring to a degree of permanent depression. 10

11 Increased competition and predation by pink salmon released by the Prince William Sound Aquaculture Corporation may be suppressing the Pacific herring population in the Prince William Sound. To achieve long-term ecosystem-based management of the Pacific herring in competition with pink salmon, we propose the initial testing and long-term monitoring of zooplankton in highly concentrated spawning areas throughout the Prince William Sound. The major pink salmon spawning grounds in Prince William Sound are specifically around the eastern Prince William Sound, Coghill River, and the Montague Island District (Fried). In consideration of these major spawning grounds and the locations of the five PWSAC pink hatcheries, we propose the foundation of a Pacific herring hatchery in Swanson Bay, Bainbridge Island in Prince William Sound to reduce juvenile herring predation by pink salmon and competition for zooplankton. The possibility of another major oil spill would be devastating and is to be considered a direct threat to the species; however, it is well managed and controlled by the Alyeska Pipeline Service Company's Ship Escort and Response Vessel System, which entails the enactment of escort tugs and over 300 employed personnel for immediate oil spill response (Alyeska Pipeline Service Company 2011). Lastly, we propose the founding of an advisory committee to discuss and communicate with the Alaska Department of Fish and Game and the Alaska Board of Fisheries regarding the proposed zooplankton testing, Pacific herring hatchery, water testing, funding management, and bycatch management. A continuous problem prohibiting the survival of the Prince William Sound ecosystem is bycatch. There is an average of 27, pounds of fishing bycatch in herring alone (National Marine Fisheries Service 2011). The amount of bycatch coupled with the standing population 11

12 may be a factor in the population suppression. Several steps should be addressed in order to stabilize and optimize the future Prince William Sound biomass and improve the fishing economy. It is extremely essential to enforce the current legal standings for fisherman to throw dead or injured bycatch overboard. Throwing away dead or injured fish is not beneficial to the economy. The "Bycatch to Food Banks" program has been supplying over 25 million pounds of bycatch from Bristol Bay to hunger relief corporations across the United States since 1994 (Welch 2011). The donations will aim to decrease the number of endangered species or species with low spawning biomass numbers. Another obstacle that should be addressed is the commercial fishing vessel monitoring. We propose the mandatory use of cameras for fishing vessels in the Prince William Sound. Four cameras will be placed around the cargo hold to ensure that no fish are being thrown overboard. The Alaska Board of Fisheries, NOAA, or the Prince William Sound Aquaculture Corporation are among the options for camera monitoring and management. The advisory committee would reach this decision as an agreement and propose further bycatch management options. Funding Management We estimate an initial cost of $868,000 with an additional estimated annual cost of $340,000 to run the program. In regard to funding management, we propose initiating a 1% tax of the gross income of Prince William Sound commercial fishing vessels as well as asking for grants and financial aid from the National Oceanic and Atmospheric Administration, the Alaska Department of Fish and Game, and the Prince William Sound Aquaculture Corporation. Once the hatchery is up and running, we could harvest a portion of the return year s spawning biomass 12

13 for cost recovery. Any further funding management would be discussed by the advisory committee and presented to the Alaska Board of Fisheries. Conclusion The Prince William Sound fisheries are valuable economical resources. The population of the pink salmon is increasing, and compromising other valuable economical resources. By introducing a Pacific herring hatchery to Swanson Bay, Prince William Sound, we aim to restore the herring population and re-open the Pacific herring fishery within the Sound. Though commercial fishing of Pacific herring isn t the most valuable economical revenue in the Prince William Sound, many other fish rely on the herring as a valuable food source. By effectively managing the Pacific herring population in Prince William Sound, we can bring back the valuable Alaskan fishery and restore balance to the Prince William Sound ecosystem. 13

14 References Crestin, P., & Crestin, S. (2002, June 16). Cruising Prince William Sound. Retrieved November 12, 2011, from pws_glacier_bay/ Cline, D. (2005, May). Special Ecological Sights in Alaska's Eastern Prince William Sound & Copper River Delta. National Wildlife Federation. Mundy, Phillip R. (ed.) The Gulf of Alaska: Biology and Oceanography. Alaska Sea Grant College Program, University of Alaska, Fairbanks Stabeno, P. J., Bond, N. A., Hermann, A. J., Katchel, N. B., Mordy, C. W., & Overland, J. E. (Eds.). (2004). Meteorology and Oceanography of the Northern Gulf of Alaska. Retrieved from promis_misc/ccrvol24issue7-8.pdf Alaska Department of Fish and Game. (2011). Pacific herring (Clupea Pallasii). Retrieved November 12, 2011, from index.cfm?adfg=herring.main Lassuy, D.R Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (Pacific Northwest)--Pacific herring. U.S. Fish Wildl. Serv. Biol. Rep. 82(11.126).U.S. Army Corps of Engineers, TR-EL pp. Alaska Department of Fish and Game. (2011). Fishery Overview. In Commercial Fisheries. Retrieved October 15, 2011, from index.cfm?adfg=fishingcommercialbyfishery.main Collins English Dictionary. (2011). Metamorphosis [dictionary]. Retrieved October 9, 2011, from Dictionary.com website: Hakanson, L., Stabo, H. R., & Bryhn, A. C. (2010). The Fish Production Potential of the Baltic Sea: A New General Approach for Optimizing Fish Quota Including a Holistic Management Plan Based on Ecosystem Modeling. Springer. Fairbanks Fish and Wildlife Field Office. (2009, March 3). Cyber Salmon. Retrieved from U.S. Fish and Wildlife Service website: Alyeska Pipeline Service Company. (2011). The Ship Escort/Response Vessel System. Retrieved from Alyeska Pipeline Service Company website: Alaska Department of Fish and Game. (2011). Pink salmon Species Profile. Retrieved from 14

15 Eggers, D.M., L.R. Peltz, B.G. Bue, and T.M. Willette, Trends in the abundance of hatchery and wild stocks of pink salmon in Cook Inlet, Prince William Sound, and Kodiak Island, Alaska. Can. Spec. Pub. Fish. Aquat. Sci. Alaska Department of Fish and Game. (1994). Pink salmon. Retrieved from Aidan, R. M. (2003). Biology of the Salmon shark (Lamna ditropis). Retrieved from ReefQuest Centre for Shark Research website: Roman, B. (n.d.). Salmon shark. Retrieved from Ichthyology at the Florida Museum of Natural History website: SalmonShark/SalmonShark.html McNair, M., and J.S. Holland, FRED 1992 Annual Report to the Alaska State Legislature. Number 127. Alaska Department of Fish and Game, Fisheries Rehabilitation, Enhancement and Development Division, P.O. Box 25526, Juneau, AK. Kron, T. (2009). Pacific herring. In Prince William Sound Salmon Enhancement Programs and Considerations Relative to Wild Stocks. Retrieved from Exxon Valdez Oil Spill Trustee Council website: recovery/status_herring.cfm Prince William Soundkeeper. (2010). Retrieved from Buckhorn, M. (2011). Importance of the prince william sound herring fishery to the people. Discussion presented at Mat-Su Career and Technical High School, Wasilla, Alaska. Cedre. (2011, May). Exxon Valdez: The Accident. Retrieved from Cedre website: Mouse Genome Database (MGD), Gene Expression Database (GED), Mouse Tumor Biology (MTB), Gene Ontology (GO), & MouseCyc. (2011, November 23). Mammalian Phenotype Browser. Retrieved November, 2011, from The Jackson Laboratory website: Westernhagen, H. V., & Rosenthal, H. (n.d.). Helgoland Marine Research: Vol. 34. On condition measurements in Pacific herring larvae. Springer. Spies, R. B. (2007). Long-term Ecological change in the Northern Gulf of Alaska. Neff, J. M., & Stubblefeild, W. A. (1999). Chemical and Toxicological Evaluation of Water Quality Following the Exxon Valdez Oil Spill. Fried, S. M., Bue, B. G., Sharp, D., & Sharr, S. (n.d.). Injury to Spawning Areas and an Evaluation of Spawning Escapement Enumeration of. Retrieved from Alaska Department of Fish and Game website: vol1/ pdf 15

16 Steffen, B. (2002). Cordova Rose Lodge. Retrieved from Alaska Internet Services website: National Marine Fisheries Service, Northwest Fisheries Science Center, & Alaska Fisheries Science Center. (n.d.). Environmental History and Features of Puget Sound. Retrieved from: techmemos/tm45/background.htm Pacific herring Clupea pallasii. (1989) Retrieved from rwqcb3/water_issues/programs/duke_energy/docs/sampling/pacificherring.pdf Kawana, M., Urawa, S., Anma, G., Kamei, Y., Shoji, T., Fukuwaka, M. A.,... Myers, K. W. (n.d.). Thermally-Marked Maturing Pink salmon in the Gulf of Alaska in the Summer of Retrieved from publications/documents/pdf%201999/421(japan).pdf 16

17 Figures Figure 1 Map of Prince William Sound between the Kenai Peninsula and the city of Cordova is enclosed by three principal barrier islands: Montague Island, Hinchinbrook Island, and Hawkins Island. (Source: ( icleid/583/language/en-us/midnight-ecological-disaster--exxon-valdez-remembered.aspx) 17

18 Figure 2 Alaska Map displaying the Alaska Coastal Current and the Alaska Gyre rotation in the Gulf of (Source: 8&tbm=isch&tbnid=UB_ryNJvuU_R9M:&imgrefurl= 3_CoHxUeJG8GM&imgurl= 501&ei=6RLXTtbhKq79iQLfxom3CQ&zoom=1&iact=rc&dur=356&sig= &page=1&tbnh=136&tbnw=176&start=0&ndsp=30&ved=1t:429,r:2,s:0&tx=124&ty=93) 18

19 Figure 3 Abundance and Recruitment in millions and total Biomass in tons of Pacific herring in Prince William Sound (Source: Figure 4 Top: A normal Pacific herring larva with a normal jaw, normal pericardium, normal yolk, and a straight spine. Middle: A Pacific herring larva exposed to low levels of oil exhibiting a normal jaw, normal pericardium, yolk edema, and a straight spine. Bottom: A Pacific herring larva exposed to high levels of oil exhibiting a deformed jaw, pericardial edema, yolk edema, and a curved spine. 19

20 (Source: df) Figure 5 Alaska Commercial Pink Salmon Catches & Value from 1878 to 2011 (Source: 20

21 Figure 6 Commerical catch of pink salmon in Prince William Sound prior to and during hatchery operation, in millions. (Source: 21

22 Figure 7 Prince William Sound Pink Salmon Return from 1970 to 1997 (Source: 22