Daryl Parkyn - Academia.edu (original) (raw)

Papers by Daryl Parkyn

Proceedings of the Royal Society B: Biological Sciences

Species delimitation is a major quest in biology and is essential for adequate management of the ... more Species delimitation is a major quest in biology and is essential for adequate management of the organismal diversity. A challenging example comprises the fish species of red snappers in the Western Atlantic. Red snappers have been traditionally recognized as two separate species based on morphology: Lutjanus campechanus (northern red snapper) and L. purpureus (southern red snapper). Recent genetic studies using mitochondrial markers, however, failed to delineate these nominal species, leading to the current lumping of the northern and southern populations into a single species ( L. campechanus ). This decision carries broad implications for conservation and management as red snappers have been commercially over-exploited across the Western Atlantic and are currently listed as vulnerable. To address this conflict, we examine genome-wide data collected throughout the range of the two species. Population genomics, phylogenetic and coalescent analyses favour the existence of two indepe...

Genetica, 2018

The greater amberjack (Seriola dumerili) is a commercially and recreationally important marine fi... more The greater amberjack (Seriola dumerili) is a commercially and recreationally important marine fish species in the southeastern United States, where it has been historically managed as two non-mixing stocks (Gulf of Mexico and Atlantic). Mark-recapture studies and analysis of mitochondrial DNA have suggested the two stocks are demographically independent; however, little is currently known about when and where spawning occurs in Gulf of Mexico amberjack, and whether stock mixture occurs on breeding grounds. The primary objective of this study was to quantify stock mixture among breeding populations of amberjack collected from the Atlantic and Gulf of Mexico. Genetic data based on 11 loci identified very low, though statistically significant differentiation among Gulf of Mexico samples (G = 0.007, [Formula: see text] = 0.009; all P = 0.001) and between reproductive adults collected from two spawning areas (G = 0.007, [Formula: see text] = 0.014; all P = 0.001). Naïve Bayesian mixture...

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Rates of loss of juvenile red drum Sciaenops ocellatus (ϳ85 mm total length) stocked out of seaso... more Rates of loss of juvenile red drum Sciaenops ocellatus (ϳ85 mm total length) stocked out of season were estimated using hatchery releases and ultrasonically tagged fish in Pumpkin and May creeks in the Chassahowitzka National Wildlife Refuge on the Gulf coast of Florida. In Pumpkin Creek, approximately 7,000 of the 10,000 fish released on 27 June 2000 survived combined transport mortality (2%) and 24-h acute mortality (28 Ϯ 8.7% [mean Ϯ SE] n ϭ 6). In May Creek, approximately 5,100 of the 10,000 fish released on 29 June 2000 survived combined transport (7.5-10%) and 24-h acute (44 Ϯ 0%, n ϭ 2) mortality. Catch curve estimates of the instantaneous ''rate of loss'' (mortality or emigration) within 5 d were 0.46/d and 0.50/d for Pumpkin and May creeks, respectively. Red drum with ultrasonic transmitters (n ϭ 12) also rapidly ''disappeared'' from the creeks within 4 d after release. These are the first estimates of postrelease rate of loss for juvenile red drum released out of season on the west coast of Florida. Understanding the causes of this overall rapid rate of loss will be critical to evaluating the success of out-of-season releases of red drum in Florida.

Advances in Zoology and Botany, 2015

The effect of solid-body blocking in a large (257 l) Blazka-style respirometer was examined in ga... more The effect of solid-body blocking in a large (257 l) Blazka-style respirometer was examined in gag Mycteroperca microlepis. Gag ranging from 376-690 mm total length were tested at velocities from 10 to 91 cm s-1. The solid blocking effect (SBE) due to fish size, swimming speed, and water temperature was investigated by direct measurement of flow velocity at the area of the fish's maximum girth as compared to measurements at the rear (center) of the swimming chamber. Three models were compared as corrections for the SBE: the standard Bell and Terhune (BT), a novel modification of the Bell and Terhune (MBT) developed in this study, and the Bernoulli equation. Although the fit was good, the commonly used BT model consistently underestimated solid-blocking effect over the speeds tested (R 2 adj = 0.980) whereas the MBT and Bernoulli models provided better fits (both with R 2 adj = 0.993). The MBT model, with refined parameters for the fish body shape coefficient and fractional surface area exponent, yielded the best fit for observed data across all speeds for which gag were tested. This study also demonstrated that in Blazka-style respirometers, corrections were needed to account for SBE where fish occupied >10% of the cross-sectional area of the swimming chamber.

Bulletin of Marine Science Miami, Dec 31, 2004

Sex-specific age and growth were determined for white grunt, Haemulon plumieri (Lacepède, 1801), ... more Sex-specific age and growth were determined for white grunt, Haemulon plumieri (Lacepède, 1801), from their main fishing area on the Gulf coast of Florida. In total, 4043 fish were collected using hook-and-line or trap gear: 2617 from the central and 1426 from the north-central Gulf coast of Florida. White grunt were aged reliably using thin-sections of sagittal otoliths. Both marginal-increment analysis and chemical marking with oxytetracycline indicated that one annulus was deposited in a 12-mo period, with the opaque zone forming mainly during May. Ages of white grunt ranged from 0-18 yrs, and fish ranged in size from 7-41 cm total length. White grunt from the north-central region were larger at age than those from the central region, and males attained a larger size than females in both regions. Asymptotic lengths of males and females combined ranged from 296-343 mm total length. Comparatively, white grunt from the Gulf coast of Florida were of similar size-at-age as fish from southeastern (Atlantic) Florida but were smaller than white grunt from North and South Carolina. Regional growth differences of white grunt are problematic for any comprehensive fishery management plan on a Florida-wide, Gulf-wide, or southeastern U.S-wide basis. Grunts of the family Haemulidae, and in particular white grunt, Haemulon plumieri (Lacepède, 1801), are important in recreational and commercial fisheries in the southeastern U.S. Most (>95%) of the total annual harvest of white grunt in the southeastern U.S. is landed in Florida. Approximately 85%-90% of the landings in Florida are from the west coast of Florida (inclusive of Monroe county, which includes most of the Florida Keys), with only 10%-15% from the east coast (Murphy et al., 1999). Total annual landings from the west coast of Florida peaked at 1040-1410 metric tons (mt) during 1989-1995, of which the recreational hook-and-line fishery was ~65%-70%, the headboat hook-and-line fishery was 20%-28%, and the commercial hook-and-line and trap harvest was 5%-20% in any one year (Murphy et al., 1999). From 1996-1998, total annual harvest of white grunt from the west coast of Florida decreased to ~850 mt per year (Murphy et al., 1999), but has since continued to increase to catch levels reported in the early 1990s (National Marine Fisheries Service Statistics, www.st.nmfs.gov). Currently, white grunt is an unregulated species with respect to daily bag, sizelimit, and total allowable catch on the west coast of Florida, both at the state level (Florida Fish and Wildlife Conservation Commission (FFWCC), Tallahassee) and the federal level (exclusive of Florida Keys) (Gulf of Mexico Fishery Management Council, Tampa). In 1998, the Florida Marine Fisheries Commission (FMFC, now the FFWCC) began public meetings to consider implementation of statewide regulations for white grunt (FMFC, 1998). The proposed regulations were to include a 305-mm (12 in) total length limit and a 20-fish aggregate daily bag limit. At the time, however, basic demographics of white grunt from the core area of the fishery, the Gulf coast of Florida, were unknown. Age and growth data were only available for white grunt

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ABSTRACT The distribution of threatened Gulf of Mexico sturgeon Acipenser oxyrinchus desotoi (her... more ABSTRACT The distribution of threatened Gulf of Mexico sturgeon Acipenser oxyrinchus desotoi (hereafter referred to as Gulf sturgeon) in the Suwannee River estuary, Florida, was examined relative to the distribution of benthic invertebrate prey and environmental variables (salinity, temperature, dissolved oxygen, and sediment type) to determine potential foraging areas within the estuary. Eighteen Gulf sturgeon (1,279–2,010 mm total length, 15.25–53.25 kg) were netted at the mouth of the Suwannee River during their spring upriver migration in 2001 and surgically implanted with ultrasonic tags. These sturgeon were subsequently tracked as they migrated seaward out of the Suwannee River and into the estuary in fall 2001 and as they returned to the estuary in spring 2002 to migrate upriver again. Invertebrates and sediment type were identified in diver-collected cores from the Suwannee River estuary during spring 2002. Thirteen of the 18 tagged Gulf sturgeon were relocated in the Suwannee River estuary. Eight were located from early November through mid-December 2001 (fall seaward migration), and 10 were located from mid-March through mid-April 2002 (spring upriver migration). Gulf sturgeon during fall 2001 and spring 2002 were associated with areas composed mostly of sand that contained high abundances of known benthic prey, primarily the brachiopod Glottidia pyramidata and, secondarily, amphipods Ampelisca spp. and brittle stars (Amphiuridae and Ophiactidae). Canonical correspondence analysis and examination of temperature and salinity at relocation positions of Gulf sturgeon during the fall 2001 and spring 2002 suggest differential use of the Suwannee River estuary during the two seasons. Compared with fall, sturgeon in the spring were found closer inshore, where the water was less saline and warmer, and they were concentrated in areas with greater abundance of their primary prey, brachiopods. Specific areas within the Suwannee River estuary therefore appear to be potential spring foraging habitats for threatened Gulf sturgeon.

Fishery Bulletin- National Oceanic and Atmospheric Administration

Observations on the distribution and activities of rockfish, Sebastes spp., in Saanich Inlet, Bri... more Observations on the distribution and activities of rockfish, Sebastes spp., in Saanich Inlet, British Columbia, from the Pisces IV submersible. DJ Murie, DC Parkyn, BG Clapp, GG Krause Fishery Bulletin 92:22, 313-323, 1994. ...

Marine and Coastal Fisheries, 2014

Taylor & Francis makes every effort to ensure the accuracy of all the information (the "Content")... more Taylor & Francis makes every effort to ensure the accuracy of all the information (the "Content") contained in the publications on our platform. Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Versions of published Taylor & Francis and Routledge Open articles and Taylor & Francis and Routledge Open Select articles posted to institutional or subject repositories or any other third-party website are without warranty from Taylor & Francis of any kind, either expressed or implied, including, but not limited to, warranties of merchantability, fitness for a particular purpose, or non-infringement. Any opinions and views expressed in this article are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor & Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions It is essential that you check the license status of any given Open and Open Select article to confirm conditions of access and use.

Greater amberjack, Seriola dumerili, is a pelagic reef fish that is managed in the US as two sepa... more Greater amberjack, Seriola dumerili, is a pelagic reef fish that is managed in the US as two separate stocks, the Gulf and the Atlantic. The most recent stock assessment for the Gulf stock found it to be overfished and undergoing overfishing. Sex-specific spatial distribution and exploitation may contribute to our understanding of the stock’s overexploitation. This may be important for greater amberjack since schools in some regions may predominantly be one sex or the other and, based on the fisheries, amberjack may be subject to sex-specific mortality. These factors may lead to sex ratios that are highly skewed from an assumed ratio of 1:1. Altered sex ratios have been found to influence population dynamics in sex changing fish, and it may be that in a gonochoristic fish that exhibits sexually dimorphic growth, such as greater amberjack, there may also be an influence. To explore the potential affects, a range of sex ratios based on previous and ongoing studies were incorporated in...

The most recent stock assessment for Gulf of Mexico greater amberjack Seriola dumerili found it t... more The most recent stock assessment for Gulf of Mexico greater amberjack Seriola dumerili found it to be overfished and undergoing overfishing. Sex-specific spatial distribution and exploitation may be important for greater amberjack because of sex‑specific mortality due to minimum size limits and possible regional skewing of sex ratios. Being able to non-lethally determine the sex of a fish prior to its release in tagging or discard studies would provide needed information on sex ratios, sex-specific migration patterns, and sex-specific mortality rates. To address this issue, a non-lethal method of sex determination was developed using external features of the urogenital pores. Urogenital catheterization was then applied to verify the sex and obtain oocyte samples from females. Of the 194 fish that had their sex verified, 193 were sexed correctly yielding an accuracy of 99.5%. Relative maturation status of females was determined from oocyte samples collected via urogenital catheteriza...

Gulf of Mexico greater amberjack Seriola dumerili have been designated as currently overfished an... more Gulf of Mexico greater amberjack Seriola dumerili have been designated as currently overfished and undergoing overfishing. Release mortality rates for amberjack in the Gulf of Mexico are unknown, yet releases are projected to increase as regulations become more restrictive. In this study, 1,493 amberjack were tagged and released to estimate release mortality. To date, 11.7% of the released fish have been recaptured, with only 0.3% suffering acute mortality. Recapture of amberjack was proportional to initial capture depth, which indicated that fish did not have increased release mortality with increasing depth of capture. Temperature-depth profiles of hooked amberjack obtained using Sensus Ultra data loggers showed varying but rapid ascent rates from 0.2 m/sec to as high as 1.2 m/sec. Lack of a typical depth/release mortality relationship may be due to amberjack self-venting or “blowing bubbles” when ascending, with the spontaneous release of gas from their swim bladders increasing w...

Greater amberjack Seriola dumerili in the Gulf of Mexico are overfished, yet their population dyn... more Greater amberjack Seriola dumerili in the Gulf of Mexico are overfished, yet their population dynamics are still poorly understood and age and growth over most of its exploitation range is unknown. In cooperation with state and federal fisheries agencies in the southeastern U.S., a total of 1,838 fish from 74 to 1829 mm fork length were collected during 1989 to 2008 and sagittae were extracted for aging. Ages and growth were compared for charterboat, private recreational, headboat, and commercial fisheries in the Gulf, as well as fishery-independent sampling. Greater amberjack ranged in age from young-of-year to 15 years, and females >4 years old were larger at age than males. Growth of greater amberjack was similar for private, charter, and headboat fisheries. The commercial hook-and-line fishery caught the largest individuals in a cohort for ages 1-4, in conjunction with a greater minimum size regulation. A subsample of amberjack in 2006-2008 also had pectoral finrays removed f...

Greater amberjack Seriola dumerili in the eastern United States are currently managed as two dist... more Greater amberjack Seriola dumerili in the eastern United States are currently managed as two distinct stocks, with one stock residing in the Gulf of Mexico and a second along the Atlantic Coast (including the Florida Keys). Support for independent management of the two stocks is based on both tagging and molecular data. Current management assumes mixing within the Gulf of Mexico stock. However, tagging data suggest that trans-regional mixing may be an infrequent event, and it is possible that some degree of geographic structure exists in the Gulf of Mexico stock. Studies have found otolith shape useful in differentiating between fish stocks of many species. This study examines otoliths of Gulf of Mexico greater amberjack to determine if they differ morphologically among subregions in the Gulf of Mexico. A combination of shape indices and harmonics calculated using elliptical Fourier analysis was used to describe otolith shape. No significant differences were seen between left and ri...

Marine and Coastal Fisheries Dynamics Management and Ecosystem Science

Stock assessments for the Gulf of Mexico (Gulf) Greater Amberjack Seriola dumerili continue to de... more Stock assessments for the Gulf of Mexico (Gulf) Greater Amberjack Seriola dumerili continue to designate the stock as overfished and undergoing overfishing, despite increasing regulatory measures. Knowledge of sex-specific spatial distribution and fishing mortality may contribute to our understanding of the stock’s overexploitation, especially since Greater Amberjacks may be subject to sex-specific mortality resulting from minimum size regulations. Currently, the sex ratio of the stock is assumed to be 1:1. An average and range of sex ratios were estimated for the Gulf stock based on sampling of fish landed in the recreational and commercial fisheries and based on released fish that were nonlethally sexed during a tagging study of sex-specific movement patterns and release mortality. The nonlethal method of sex determination was developed based on external features of the urogenital region; urogenital catheterization was used to validate the external sexing and to collect oocyte sam...

Marine and Freshwater Research

Accurate data on fish diets play a fundamental role in understanding trophic interactions and hel... more Accurate data on fish diets play a fundamental role in understanding trophic interactions and help explain habitat-use patterns and nutrient flow between systems. In the present study, the diet of a reef fish was characterised by visual identification and augmented with an alternative, non-visual-based method of diet analysis to generate identifications for macerated prey items that are challenging to identify. A DNA-based approach was capable of identifying prey items to the species level and, when combined with conventional visual analysis, helped reduce the number of unknown organisms recovered from stomach contents of French grunt.

The Journal of experimental biology, 2000

Spectral and polarisation sensitivity were compared among juvenile (parr) rainbow trout (Oncorhyn... more Spectral and polarisation sensitivity were compared among juvenile (parr) rainbow trout (Oncorhynchus mykiss), steelhead (O. mykiss), cutthroat trout (O. clarki clarki), kokanee (O. nerka) and brook char (Salvelinus fontinalis) using multi-unit recording from the optic nerve. Although reared under the same conditions, differences in photopic spectral sensitivity were evident. Specifically, ON-responses were co-dominated by L- and M-cone mechanisms in all fish except O. nerka, consistent with an M-cone mechanism sensitivity. The sensitivity of OFF-responses was dominated by the M-cone mechanism for all fish, but O. mykiss appeared to show an additional contribution from the L-cone mechanism. Using chromatic adaptation, an independent ultraviolet-sensitive mechanism is described for the first time for the salmonid genus Salvelinus. In addition, this ultraviolet-cone mechanism was present in the members of the genus Oncorhynchus that were examined. Thus, ultraviolet sensitivity appears...

Transactions of the American Fisheries Society, 2005

Page 1. 975 Transactions of the American Fisheries Society 134:975990, 2005 [Article] Copyright ... more Page 1. 975 Transactions of the American Fisheries Society 134:975990, 2005 [Article] Copyright by the American Fisheries Society 2005 DOI: 10.1577/T04-100.1 Distribution of Gulf of Mexico Sturgeon in Relation to Benthic ...