J. Zamon - Academia.edu (original) (raw)
Papers by J. Zamon
Northwestern Naturalist, 2007
... We thank R Emmett, B Hanson, J Estes, and three anon-ymous reviewers for providing critiques ... more ... We thank R Emmett, B Hanson, J Estes, and three anon-ymous reviewers for providing critiques of the man-uscript. C Wilson at the Northwest Fisheries Science Center provided critical library services to our re-mote field site. ...
We conducted a study to assess the effects of ocean conditions and climate change on salmon growt... more We conducted a study to assess the effects of ocean conditions and climate change on salmon growth. Juvenile coho salmon (Oncorhynchus kisutch) were collected off the west coast of British Columbia and Alaska in 1998-2000. Sea surface temperature was higher in 1998 by about 2-3°C due to a warm El Niño that was followed by a cool La Niña. Coho salmon were two-fold smaller in southern British Columbia than in Alaska in 1998. Lipid and energy contents were also lower in coho from southern British Columbia in 1998. These differences disappeared in 1999-2000. Coho salmon consumed on average about 10% of their body weight per day. These feeding rates did not vary significantly between regions or years. Simulations performed using a bioenergetic model showed that summer growth was reduced by only 10 grams when temperature increased by 3°C, but could easily vary by a factor of two with small differences in prey caloric contents. Our analyses suggest that an increase in sea surface temperature affects salmon growth through changes in prey community structure rather than by a diminution in feeding rates or an increase in metabolic rates.
Increasingly diverse interests in commercial and recreational use of marine resources are creatin... more Increasingly diverse interests in commercial and recreational use of marine resources are creating new challenges for coastal ocean management. One concern of increased offshore use and development off the Oregon coast is the potential impact on marine bird populations. We summarized the primary surveys of seabird breeding colonies and at-sea distribution along the Oregon coast to describe spatial patterns in species distribution and identify gaps where additional data are needed. The abundance of breeding birds during the summer (over 1 million in total, primarily Common Murre Uria aalge and Leach's Storm-Petrel Oceanodroma leucorhoa) is greatest in northern and southern Oregon due to the availability of breeding habitat on large offshore rocks and islands. While there are fewer breeding colonies along sandy shorelines, the adjacent coastal waters are still frequented by breeding birds and nonbreeding migrants, but generally in lower densities during summer. Seabird density, and likely potential interaction with offshore structures, is greatest nearshore and steadily declines to lowest levels beyond the outer continental shelf. Dynamic soaring species, however, which have a greater potential to interact with taller structures such as wind turbines, tend to be more common on the middle to outer shelf. Species composition also changes dramatically among seasons. Low flying (< 30 m above sea level) diving species dominate in most seasons, however, which has potential conservation implications for interactions with structures above and below the water's surface. Given the abundance of storm-petrels, increased light pollution is also a concern for these and other nocturnal, phototactic species. Dramatic declines or redistributions have occurred at some breeding colonies, indicating long-term planning should consider changing habitat requirements. The greatest data needs currently include fall/winter/spring at-sea distribution, summer distribution off southern Oregon, and more accurate estimates and monitoring of burrow-nesting seabirds. Oregon's coastal waters provide habitat for a large portion of breeding and nonbreeding marine birds along the U.S. west coast and a thorough knowledge of their spatial distribution, seasonal abundance, and migration corridors is critical for well-informed marine spatial planning.
... Acoustic signals from the receiver were recorded to a hard-drive using ISHMAEL and a NI 6062E... more ... Acoustic signals from the receiver were recorded to a hard-drive using ISHMAEL and a NI 6062E DAQ card or the internal PC sound card. 4 Page 8. Towed Arrays - Monitoring ... 9 * 40 Phocoena phocoena 10 1.4 44 Phocoenoides dalli 14 3.4 46 Physeter macrocephalus 1 1 ...
ii Performance Metrics: Population Structure, Life History Diversity, and Growth
Fisheries Research, 2013
We used a combination of seabird data (both fishery-dependent and fishery-independent) and fishin... more We used a combination of seabird data (both fishery-dependent and fishery-independent) and fishingeffort data to evaluate the relative fisheries risk of five west coast groundfish fisheries and one shrimp fishery to black-footed (Phoebastria nigripes), short-tailed (P. albatrus) and Laysan albatrosses (P. immutabilis). To assess risk, an overlap index was derived as the product of total fishing effort and at-sea survey density of black-footed albatross. This index was used as the primary tool to estimate overlap with the endangered, relatively rare short-tailed albatross, which show similar habitat utilization from satellite telemetry tracks. Telemetry data indicate Laysan albatross primarily occur offshore beyond observed fishing effort. Black-footed and short-tailed albatross-fishery overlap was highest at the shelfbreak (201-1000 m) north of 36 • N. Overlap and reported albatross mortality indicate that the sablefish (Anoplopoma fimbria) longline and Pacific hake (Merluccius productus) catcher-processor fisheries pose the greatest risk to these species; the near-shore rockfish (Seabastes spp.) longline, pink shrimp (Pandalus jordani) trawl, California halibut (Paralichthys californicus) trawl, and non-hake groundfish trawl fisheries pose relatively little risk. Implementing proven seabird bycatch-reduction measures will likely minimize albatross mortality in the highest-risk fishery, sablefish longline.
Northwestern Naturalist, 2007
... We thank R Emmett, B Hanson, J Estes, and three anon-ymous reviewers for providing critiques ... more ... We thank R Emmett, B Hanson, J Estes, and three anon-ymous reviewers for providing critiques of the man-uscript. C Wilson at the Northwest Fisheries Science Center provided critical library services to our re-mote field site. ...
We conducted a study to assess the effects of ocean conditions and climate change on salmon growt... more We conducted a study to assess the effects of ocean conditions and climate change on salmon growth. Juvenile coho salmon (Oncorhynchus kisutch) were collected off the west coast of British Columbia and Alaska in 1998-2000. Sea surface temperature was higher in 1998 by about 2-3°C due to a warm El Niño that was followed by a cool La Niña. Coho salmon were two-fold smaller in southern British Columbia than in Alaska in 1998. Lipid and energy contents were also lower in coho from southern British Columbia in 1998. These differences disappeared in 1999-2000. Coho salmon consumed on average about 10% of their body weight per day. These feeding rates did not vary significantly between regions or years. Simulations performed using a bioenergetic model showed that summer growth was reduced by only 10 grams when temperature increased by 3°C, but could easily vary by a factor of two with small differences in prey caloric contents. Our analyses suggest that an increase in sea surface temperature affects salmon growth through changes in prey community structure rather than by a diminution in feeding rates or an increase in metabolic rates.
Increasingly diverse interests in commercial and recreational use of marine resources are creatin... more Increasingly diverse interests in commercial and recreational use of marine resources are creating new challenges for coastal ocean management. One concern of increased offshore use and development off the Oregon coast is the potential impact on marine bird populations. We summarized the primary surveys of seabird breeding colonies and at-sea distribution along the Oregon coast to describe spatial patterns in species distribution and identify gaps where additional data are needed. The abundance of breeding birds during the summer (over 1 million in total, primarily Common Murre Uria aalge and Leach's Storm-Petrel Oceanodroma leucorhoa) is greatest in northern and southern Oregon due to the availability of breeding habitat on large offshore rocks and islands. While there are fewer breeding colonies along sandy shorelines, the adjacent coastal waters are still frequented by breeding birds and nonbreeding migrants, but generally in lower densities during summer. Seabird density, and likely potential interaction with offshore structures, is greatest nearshore and steadily declines to lowest levels beyond the outer continental shelf. Dynamic soaring species, however, which have a greater potential to interact with taller structures such as wind turbines, tend to be more common on the middle to outer shelf. Species composition also changes dramatically among seasons. Low flying (< 30 m above sea level) diving species dominate in most seasons, however, which has potential conservation implications for interactions with structures above and below the water's surface. Given the abundance of storm-petrels, increased light pollution is also a concern for these and other nocturnal, phototactic species. Dramatic declines or redistributions have occurred at some breeding colonies, indicating long-term planning should consider changing habitat requirements. The greatest data needs currently include fall/winter/spring at-sea distribution, summer distribution off southern Oregon, and more accurate estimates and monitoring of burrow-nesting seabirds. Oregon's coastal waters provide habitat for a large portion of breeding and nonbreeding marine birds along the U.S. west coast and a thorough knowledge of their spatial distribution, seasonal abundance, and migration corridors is critical for well-informed marine spatial planning.
... Acoustic signals from the receiver were recorded to a hard-drive using ISHMAEL and a NI 6062E... more ... Acoustic signals from the receiver were recorded to a hard-drive using ISHMAEL and a NI 6062E DAQ card or the internal PC sound card. 4 Page 8. Towed Arrays - Monitoring ... 9 * 40 Phocoena phocoena 10 1.4 44 Phocoenoides dalli 14 3.4 46 Physeter macrocephalus 1 1 ...
ii Performance Metrics: Population Structure, Life History Diversity, and Growth
Fisheries Research, 2013
We used a combination of seabird data (both fishery-dependent and fishery-independent) and fishin... more We used a combination of seabird data (both fishery-dependent and fishery-independent) and fishingeffort data to evaluate the relative fisheries risk of five west coast groundfish fisheries and one shrimp fishery to black-footed (Phoebastria nigripes), short-tailed (P. albatrus) and Laysan albatrosses (P. immutabilis). To assess risk, an overlap index was derived as the product of total fishing effort and at-sea survey density of black-footed albatross. This index was used as the primary tool to estimate overlap with the endangered, relatively rare short-tailed albatross, which show similar habitat utilization from satellite telemetry tracks. Telemetry data indicate Laysan albatross primarily occur offshore beyond observed fishing effort. Black-footed and short-tailed albatross-fishery overlap was highest at the shelfbreak (201-1000 m) north of 36 • N. Overlap and reported albatross mortality indicate that the sablefish (Anoplopoma fimbria) longline and Pacific hake (Merluccius productus) catcher-processor fisheries pose the greatest risk to these species; the near-shore rockfish (Seabastes spp.) longline, pink shrimp (Pandalus jordani) trawl, California halibut (Paralichthys californicus) trawl, and non-hake groundfish trawl fisheries pose relatively little risk. Implementing proven seabird bycatch-reduction measures will likely minimize albatross mortality in the highest-risk fishery, sablefish longline.