| dc.identifier.uri | http://hdl.handle.net/11401/76211 | |
| dc.description.sponsorship | This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree. | en_US |
| dc.format | Monograph | |
| dc.format.medium | Electronic Resource | en_US |
| dc.language.iso | en_US | |
| dc.publisher | The Graduate School, Stony Brook University: Stony Brook, NY. | |
| dc.type | Dissertation | |
| dcterms.abstract | In this dissertation, statistical and modeling approaches were undertaken to increase the knowledge of spiny dogfish distribution, habitat, and population dynamics including: (1), environmental preference (2), habitat modeling (3), assessing diel variation in survey catchability of spiny dogfish and key prey species and (4), elucidating how spiny dogfish distributional shifts influenced their availability to commercial fisheries. For objective (1), I estimated habitat preference for neonate (total length, TL <= 26 cm), immature (male: 26 cm < TL < 60 cm; female: 26 cm < TL < 80 cm), and mature (male: TL >= 60 cm; female: TL >= 80 cm) spiny dogfish using Northeast Fisheries Science Center (NEFSC) annual bottom trawl survey data from 1963 through 2009. Preferences were compared between dogfish stages to relate movements and distribution to environmental and reproductive behavior. In addition, I explored the influence of density-dependence on distribution. For objective (2), I analyzed the quantitative relationship between spiny dogfish occurrence and abundance with ambient environmental and temporal factors, and ecological factors (i.e., prey abundance, presence of conspecifics) in the NES LME using NEFSC survey data and generalized additive models (GAMs) to elucidate potential mechanisms underlying distributions of dogfish stages. For objective (3), I investigated diel variation on NEFSC survey catch rates and catchability and assessed the influence of temperature, depth, and Julian day on day-time capture probability. Lastly, for objective (4), I examined the spatio-temporal interactions between spiny dogfish distribution (derived from NEFSC survey data) and commercial fishers (derived from NEFSC Observer data) in the NES LME to elucidate how spiny dogfish distributional changes have impacted their availability to the fishery. I found strong ontogenetic differences in seasonal and decadal distribution and habitat preference for spiny dogfish. All dogfish stages occupied warmer, more saline, and more southerly locations in autumn compared to those available during spring. In contrast, during autumn larger spiny dogfish occupied warmer, shallower, and less saline waters whereas neonates preferred more saline waters than those surveyed. In addition, spiny dogfish appeared more aggregated during autumn than spring. Dogfish stages differed considerably regarding preferred habitat during both seasons. Density appeared related to geographic range when all dogfish stages were combined during autumn. Generalized additive modeling resulted in widespread significant nonlinear relationships throughout dogfish stages and seasons. Generally, seasonal occurrence was tightly linked to environmental properties (e.g., bottom temperature and depth) with temporal variables (e.g., year and Julian day) influential for some dogfish stages. Prey species considered for analyses included Atlantic butterfish (Peprilus triacanthus), Atlantic herring (Clupea harengus), shortfin squid (Illex sp.), longfin squid (Loligo sp.), and Atlantic mackerel (Scomber scombrus). While environment (e.g., bottom temperature and depth) and temporal (e.g., year and Julian day) variables also influenced the abundances of most dogfish stages, ecological factors (e.g., Loligo sp. and Illex sp. abundances) significantly contributed to the abundances of mature females and neonates. Spring trends in abundance identified bottom temperature as highly influential for most dogfish stages whereas during autumn ecological factors predominantly controlled abundance. Forecasted distributions under different temperature scenarios during spring generally revealed higher probabilities of spiny dogfish occurrence throughout the range during a " warmer" (BTavg +1°C) year but lower probabilities in northern regions during a " cooler" (BTavg +1°C) year. Day and night catch distributions differed significantly (padj < 0.0045) for spiny dogfish during spring and most prey species during both seasons, with larger day-time catches evident. Annual day-time catch rates exceeded night rates for most prey during both seasons, for spiny dogfish during autumn, and for both neonate and mature male spiny dogfish during spring. While larger and more frequent day-time aggregations were frequently observed for all species examined, only autumn-captured Illex sp. revealed a significant (padj < 0.0045) difference in the distribution of day and night aggregations. Most species revealed highly variable temporal CPUE during both seasons, often with higher rates during day-time. Significantly (p < 0.05) higher day-time catchability was observed for most dogfish stages and prey species during autumn but solely for mature male spiny dogfish and squid during spring. CPUE estimates adjusted for higher day-time catchability when appropriate resulted in lower CPUE estimates, suggesting the NEFSC survey is overestimating the overall and regional abundances of most species. Environmental factors frequently influenced the seasonal probability of day-time catch for all species and seasons. Fishery-dependent analyses focused on the sink gill net and otter trawl fisheries, two of the largest domestic fisheries landing spiny dogfish since 1989. While both fisheries encountered spiny dogfish throughout the NES LME during most calendar months, summer catches primarily occurred in the north whereas winter catches predominated in the south. During both seasons, spiny dogfish CPUE was more clustered (I ~ 0.3) in the SGN fishery compared to both the OT fishery (I ~ 0.15) and the survey (I ~ 0.18). Centers of spiny dogfish abundance differed significantly (p < 0.05) during each season and often differed among fisheries and the survey (padj < 0.0167). The spatial overlap between fisher effort and spiny dogfish distribution (SOE) increased with time for the SGN fishery during spring and the OT fishery during autumn, suggesting a growing portion of the stock was available to each fishery. Direct spatial overlap of spiny dogfish distribution inferred from both survey and fishery catch (SOC) revealed variable seasonal trends with interpolated overlap (SOI) often exceeding but matching trends derived directly. Vulnerability of spiny dogfish to each fishery was generally higher during autumn and has increased recently for many dogfish stages. | |
| dcterms.abstract | In this dissertation, statistical and modeling approaches were undertaken to increase the knowledge of spiny dogfish distribution, habitat, and population dynamics including: (1), environmental preference (2), habitat modeling (3), assessing diel variation in survey catchability of spiny dogfish and key prey species and (4), elucidating how spiny dogfish distributional shifts influenced their availability to commercial fisheries. For objective (1), I estimated habitat preference for neonate (total length, TL <= 26 cm), immature (male: 26 cm < TL < 60 cm; female: 26 cm < TL < 80 cm), and mature (male: TL >= 60 cm; female: TL >= 80 cm) spiny dogfish using Northeast Fisheries Science Center (NEFSC) annual bottom trawl survey data from 1963 through 2009. Preferences were compared between dogfish stages to relate movements and distribution to environmental and reproductive behavior. In addition, I explored the influence of density-dependence on distribution. For objective (2), I analyzed the quantitative relationship between spiny dogfish occurrence and abundance with ambient environmental and temporal factors, and ecological factors (i.e., prey abundance, presence of conspecifics) in the NES LME using NEFSC survey data and generalized additive models (GAMs) to elucidate potential mechanisms underlying distributions of dogfish stages. For objective (3), I investigated diel variation on NEFSC survey catch rates and catchability and assessed the influence of temperature, depth, and Julian day on day-time capture probability. Lastly, for objective (4), I examined the spatio-temporal interactions between spiny dogfish distribution (derived from NEFSC survey data) and commercial fishers (derived from NEFSC Observer data) in the NES LME to elucidate how spiny dogfish distributional changes have impacted their availability to the fishery. I found strong ontogenetic differences in seasonal and decadal distribution and habitat preference for spiny dogfish. All dogfish stages occupied warmer, more saline, and more southerly locations in autumn compared to those available during spring. In contrast, during autumn larger spiny dogfish occupied warmer, shallower, and less saline waters whereas neonates preferred more saline waters than those surveyed. In addition, spiny dogfish appeared more aggregated during autumn than spring. Dogfish stages differed considerably regarding preferred habitat during both seasons. Density appeared related to geographic range when all dogfish stages were combined during autumn. Generalized additive modeling resulted in widespread significant nonlinear relationships throughout dogfish stages and seasons. Generally, seasonal occurrence was tightly linked to environmental properties (e.g., bottom temperature and depth) with temporal variables (e.g., year and Julian day) influential for some dogfish stages. Prey species considered for analyses included Atlantic butterfish (Peprilus triacanthus), Atlantic herring (Clupea harengus), shortfin squid (Illex sp.), longfin squid (Loligo sp.), and Atlantic mackerel (Scomber scombrus). While environment (e.g., bottom temperature and depth) and temporal (e.g., year and Julian day) variables also influenced the abundances of most dogfish stages, ecological factors (e.g., Loligo sp. and Illex sp. abundances) significantly contributed to the abundances of mature females and neonates. Spring trends in abundance identified bottom temperature as highly influential for most dogfish stages whereas during autumn ecological factors predominantly controlled abundance. Forecasted distributions under different temperature scenarios during spring generally revealed higher probabilities of spiny dogfish occurrence throughout the range during a " warmer" (BTavg +1°C) year but lower probabilities in northern regions during a " cooler" (BTavg +1°C) year. Day and night catch distributions differed significantly (padj < 0.0045) for spiny dogfish during spring and most prey species during both seasons, with larger day-time catches evident. Annual day-time catch rates exceeded night rates for most prey during both seasons, for spiny dogfish during autumn, and for both neonate and mature male spiny dogfish during spring. While larger and more frequent day-time aggregations were frequently observed for all species examined, only autumn-captured Illex sp. revealed a significant (padj < 0.0045) difference in the distribution of day and night aggregations. Most species revealed highly variable temporal CPUE during both seasons, often with higher rates during day-time. Significantly (p < 0.05) higher day-time catchability was observed for most dogfish stages and prey species during autumn but solely for mature male spiny dogfish and squid during spring. CPUE estimates adjusted for higher day-time catchability when appropriate resulted in lower CPUE estimates, suggesting the NEFSC survey is overestimating the overall and regional abundances of most species. Environmental factors frequently influenced the seasonal probability of day-time catch for all species and seasons. Fishery-dependent analyses focused on the sink gill net and otter trawl fisheries, two of the largest domestic fisheries landing spiny dogfish since 1989. While both fisheries encountered spiny dogfish throughout the NES LME during most calendar months, summer catches primarily occurred in the north whereas winter catches predominated in the south. During both seasons, spiny dogfish CPUE was more clustered (I ~ 0.3) in the SGN fishery compared to both the OT fishery (I ~ 0.15) and the survey (I ~ 0.18). Centers of spiny dogfish abundance differed significantly (p < 0.05) during each season and often differed among fisheries and the survey (padj < 0.0167). The spatial overlap between fisher effort and spiny dogfish distribution (SOE) increased with time for the SGN fishery during spring and the OT fishery during autumn, suggesting a growing portion of the stock was available to each fishery. Direct spatial overlap of spiny dogfish distribution inferred from both survey and fishery catch (SOC) revealed variable seasonal trends with interpolated overlap (SOI) often exceeding but matching trends derived directly. Vulnerability of spiny dogfish to each fishery was generally higher during autumn and has increased recently for many dogfish stages. | |
| dcterms.available | 2017-09-20T16:49:40Z | |
| dcterms.contributor | Cerrato, Robert | en_US |
| dcterms.contributor | Frisk, Michael G | en_US |
| dcterms.contributor | Chapman, Demian | en_US |
| dcterms.contributor | Rago, Paul | en_US |
| dcterms.contributor | Musick, John. | en_US |
| dcterms.creator | Sagarese, Skyler Rose | |
| dcterms.dateAccepted | 2017-09-20T16:49:40Z | |
| dcterms.dateSubmitted | 2017-09-20T16:49:40Z | |
| dcterms.description | Department of Marine and Atmospheric Science. | en_US |
| dcterms.extent | 520 pg. | en_US |
| dcterms.format | Application/PDF | en_US |
| dcterms.format | Monograph | |
| dcterms.identifier | http://hdl.handle.net/11401/76211 | |
| dcterms.issued | 2013-12-01 | |
| dcterms.language | en_US | |
| dcterms.provenance | Made available in DSpace on 2017-09-20T16:49:40Z (GMT). No. of bitstreams: 1
Sagarese_grad.sunysb_0771E_11385.pdf: 28594553 bytes, checksum: 466730419ad8b915d8bc47f098d767d2 (MD5)
Previous issue date: 1 | en |
| dcterms.publisher | The Graduate School, Stony Brook University: Stony Brook, NY. | |
| dcterms.subject | Catchability, Distribution, Elasmobranch, Fisheries, Habitat, Oceanography | |
| dcterms.subject | Fisheries and aquatic sciences | |
| dcterms.title | The population ecology of the spiny dogfish in the Northeast (US) shelf large marine ecosystem: Implications for the status of the stock | |
| dcterms.type | Dissertation | |
