Charles W. Caillouet

A Vinyl Streamer Tag for Shrimp (Penaeus spp.)

Abstract This paper describes a vinyl streamer tag for use on shrimp (Penaeus spp.). The tag is light and flexible, and has little if any effect on shrimp movement or behavior. In laboratory tests, the streamer was retained by the shrimp and caused no detectable tagging mortality, while considerable mortality occurred in shrimp tagged with a Petersen tag. In field tests over a 30-day period, there were limited dislocation and loss of streamer tags, but the dye used to color the vinyl material faded. Suggestions for modification of the streamer tag are made to alleviate these two problems. Mortality in shrimp tagged with the streamer did not differ significantly from that of untagged shrimp.

Kemp's Ridley Sea Turtle (Lepidochelys kempii) Age at First Nesting

Abstract Kemps ridley sea turtle (Lepidochelys kempii) age at first nesting is the age at which an individual female successfully nests for the first time. This commentary recommends determination of the statistical distribution of age at first nesting, estimation of central tendency, and variability of age at first nesting, and application of these estimates in future age-based and life stage–based demographic modeling, as substitutes for parameter estimates based on age at sexual maturity or age at first reproduction. We hope that our commentary will encourage discussion and research on age at first nesting and its application to demographic modeling of the Kemps ridley population.

Phosphoglucomutase polymorphism in white shrimp, Penaeus setiferus☆

Abstract 1. 1. Ten phenotypes of phosphoglucomutase (PGM), were detected in abdominal muscle extracts from white shrimp ( Penaeus setiferus ) by starch-gel electrophoresis. 2. 2. The assumption that these phenotypes were under the control of five allelic genes was supported by the observed distribution of the phenotypes. 3. 3. There were no significant differences in PGM phenotype distribution between sexes or among samples of shrimp collected from Matagorda and Galveston Bays, Texas; Rockefeller Refuge and Barataria Bay, Louisiana; and the north Edisto River, South Carolina. 4. 4. The five PGM alleles observed in white and brown shrimp appear to be the same in the two species. 5. 5. Comparisons of PGM phenotype distributions and allele frequencies of white and brown shrimp suggest that the two species are closely related.

Polymorphism in phosphohexose isomerase in white shrimp, Penaeus setiferus linnaeus, and pink shrimp, P. duorarum duorarum☆

Abstract 1. 1. One- and three-banded phenotypes of phosphohexose isomerase (PHI) were observed in muscle extract of white shrimp (Penaeus setiferus Linnaeus) and in pink shrimp (P. duorarum duorarum) on starch gel zymograms. 2. 2. Based on genetic criteria, the five anodal PHI phenotypes observed on the white shrimp and pink shrimp zymograms were assumed to be under the control of four allelic genes. 3. 3. There were no significant differences in PHI phenotype distributions either between sexes or among samples of white shrimp from Calcasieu Lake, LA or Biloxi Bay, MS, or between sexes of pink shrimp from Tampa Bay, FL. 4. 4. Based upon zymogram comparisons of white and pink shrimp we concluded that the migration rates of the white and pink shrimp alleles are similar.

Kemp's Ridley Sea Turtle Saga and Setback: Novel Analyses of Cumulative Hatchlings Released and Time-Lagged Annual Nests in Tamaulipas, Mexico

Abstract Kemps ridley (Lepidochelys kempii) is the most endangered of the sea turtles. Its female population in the Gulf of Mexico suffered a major setback sometime between the ends of nesting seasons in 2009 and 2010. Prior to that, annual nests (i.e., clutches laid by multiple year-classes of nesters) at the female populations index beach in Tamaulipas, Mexico were increasing exponentially, the result of more than 4 decades of cumulative conservation efforts on land and at sea. Annual nests dropped 35.4% in 2010 and remained well below predicted levels through 2014, and annual hatchlings released (both sexes combined) also were lower in 2010–2014 compared with those in 2009. We conducted novel analyses of an available 1966–2014 time series of annual nests and annual hatchlings released on the index beach. We examined 1) the relationship between time-lagged annual nests during years 1986–2014 and cumulative hatchlings released by years 1976–2004, respectively, assuming female minimum age at maturity of 10 yrs, and 2) the time-series of time-lagged annual nests during 1986–2014 divided by cumulative hatchlings released by 1976–2004, respectively, under the same assumption. Both metrics showed extraordinary downward departures in 2010–2014, instead of expected increases. Although causes of the populations setback have not been determined with certainty, we suggest that the most expedient way to restore this populations growth would be to translocate more clutches to protective corrals, leaving fewer in situ where their survival is reduced. It could take at least 10 yrs before results of such a change in conservation practice become evident.

Swimming performance of captive-reared Kemp's ridley sea turtles Lepidochelys kempi (Garman)

Swimming performance of Kemps ridley sea turtles Lepidochelys kempi (Garman) was evaluated over a 6-month period to determine whether an exercise regine increased swimming capacity in captive reared turtles. Three experimental treatments included: (1) turtles exercised twice weekly and exposed to a weekly stamina test; (2) turtles subjected only to a weekly stamina test; and (3) non-exercised controls exposed to a single stamina test at the end of the study. No statistically significant difference in swimming capacity was detected between treatments 1 and 2, although treatment 1 turtles achieved higher performance levels than those from treatment 2. However, treatment 1 turtles exhibited fewer breaths/min (BRM) and foreflipper strokes/min (FSM) during stamina tests than did treatment 2 turtles. In contrast, control turtles (treatment 3) were unable to achieve the minimum swimming performance level. These results indicate that the swimming performances of exercised turtles significantly improved during captive rearing. The possible effects of an exercise regime on post-release survival potential are discussed.

Did Declining Carrying Capacity for the Kemp's Ridley Sea Turtle Population Within the Gulf of Mexico Contribute to the Nesting Setback in 2010−2017?

Abstract The Kemps ridley (Lepidochelys kempii) is the most endangered sea turtle species. During 1966–2017, an annual count of nests (i.e., clutches of eggs laid) has served as an annual index of Kemps ridley nesting female abundance on the Gulf of Mexico (GoM) index beach in Tamaulipas, Mexico. This index was increasing exponentially at 19% per year in 2009, but it dropped unexpectedly by more than a third in 2010 and through 2017 remained well below levels predicted. We hypothesize that pre-2010 declining carrying capacity for the Kemps ridley population within the GoM contributed to this nesting setback. We discuss pre-2010 factors that may have caused carrying capacity to decline, including degradation of the GoM ecosystem, the exponentially increasing Kemps ridley population, and declining per capita availability of neritic (i.e., postpelagic) Kemps ridley food, including natural prey and scavenged discarded bycatch from shrimp trawling. We encourage evaluations (especially those within a robust modeling framework) of this hypothesis and others put forth to explain the nesting setback to provide information needed to guide restoration of the populations progress toward recovery.