Helen R. Martins

TRANSATLANTIC DEVELOPMENTAL MIGRATIONS OF LOGGERHEAD SEA TURTLES DEMONSTRATED BY mtDNA SEQUENCE ANALYSIS

Molecular markers based on mitochondrial (mt) DNA control region sequences were used to test the hypothesis that juvenile loggerhead sea turtles (Caretta caretta) in pelagic habitats of the eastern Atlantic are derived from nesting populations in the western Atlantic. We compared mtDNA haplotypes from 131 pelagic juvenile turtles (79 from the Azores and 52 from Madeira) to mtDNA haplotypes observed in major nesting colonies of the Atlantic Ocean and Mediterranean Sea. A subset of 121 pelagic samples (92%) contained haplotypes that match mtDNA sequences observed in nesting colonies. Maximum likelihood analyses (UCON, SHADRACQ) estimate that 100% of these pelagic juveniles are from the nesting populations in the southeastern United States and adjacent Yucatan Peninsula, Mexico. Estimated contributions from nesting populations in south Florida (0.71, 0.72), northern Florida to North Carolina (0.19, 0.17), and Quintana Roo, Mexico (0.11, 0.10) are consistent with the relative size of these nesting aggregates....

COMPENSATORY GROWTH IN OCEANIC LOGGERHEAD SEA TURTLES: RESPONSE TO A STOCHASTIC ENVIRONMENT

Compensatory growth (CG, accelerated growth that may occur when an organism that has grown at a reduced rate as a result of suboptimal environmental conditions is exposed to better conditions) is considered an adaptation to variable en- vironments. Although documented thoroughly under captive conditions, CG has rarely been studied in wild populations. In their first years of life, oceanic-stage loggerhead sea turtles (Caretta caretta) have relatively little control over their geographic position or movements and thus have an extremely stochastic lifestyle with great variation in food availability and temperature. This environmental variation results in variable growth rates. We evaluate somatic growth functions of oceanic-stage loggerheads from the eastern Atlantic based on skeletochronology that allowed us to assign age and cohort to each individual. We demonstrate CG in these turtles based on three different analytical approaches: changes in coefficients of variation in size-at-age, generalized additive model regression analyses of somatic growth, and linear regression of age-specific growth rates. As a result of CG, variation in size-at-age in these juvenile loggerheads is substantially reduced. Thus, size is a better predictor of age than expected based on variation in growth rates. CG decreases with age, apparently as loggerheads gain greater control over their movements. In addition, we have evaluated for the first time in wild sea turtles the time-dependent nature of somatic growth by distinguishing among age, year, and cohort effects using a mixed longitudinal sampling design with assigned-age individuals. Age and year had significant effects on growth rates, but there was no significant cohort effect. Our results address critical gaps in knowledge of the demog- raphy of this endangered species.

Biological Studies of the Exploited Stock of the Mediterranean Locust Lobster Scyllarides Latus (Latreille, 1803) (Decapoda: Scyllaridae) in the Azores

ABSTRACT Of 565 individuals of Scyllarides latus (Latreille, 1803) from landings on Pico Island, Azores, during the summer of 1982, 55% were males, and 45% females, of which 75% were ovigerous. The mean carapace length for males and females was 92.4 mm and 94.8 mm, respectively. The weight/length relationship for males is expressed by W = 0.0020L2.825 and for females W = 0.0065L2.580. The number of eggs per brood varied from 151-356,000. The egg-bearing period lasted for approximately 6-8 weeks, with spawning starting in late June. Eggs hatched into naupliosoma larvae. The naupliosoma stage observed in an aquarium lasted approximately 40–60 min. The larvae swam with the help of their antennae. The main diet of S. latus in summer consists of limpets (Patella spp.). The principal predator of the commercial stock is the dusky grouper (Epinephelus guaza). The lobsters migrate to deeper water at the beginning of October and return to the coast in May. Molting takes place in winter. In aquaria, 7 individuals molted between 28 November and 28 February. After results of this study were known, the Secretariat of Agriculture and Fisheries of the Regional Government of the Azores changed the closed season for catching this species from 1 August-30 April to 1 May-31 August.

RNA concentration and the RNA to protein ratio in cephalopod tissues: sources of variation and relationship with growth rate

Abstract RNA and protein concentrations, and the RNA to protein ratio, were measured in four species of cephalopods, to evaluate sources of variation and the potential for using RNA concentration and the RNA to protein ratio as growth indices. In field samples of Loligo forbesi and Eledone cirrhosa , RNA concentrations and the RNA to protein ratio were higher in immature animals than in mature animals. In Loligo forbesi , values were also higher in males than in females and higher in smaller individuals than in large individuals. Both these trends are consistent with expected differences in growth rate, i.e. RNA is higher in faster growing animals. Mature female Eledone cirrhosa , a species in which the female is larger and presumably grows faster, had higher RNA concentrations than mature males. However, no such difference between the sexes was seen for immature E. cirrhosa or Todarodes sagittatus . Methods for transport and maintenance of Loligo forbesi in captivity in the Azores are described. Many of the captive squid showed poor growth and survival but results from these animals nevertheless confirmed that RNA concentrations were higher in males than in females and higher in animals with smaller gonads than in animals with large gonads. Higher protein concentrations were found in males than in females, and protein concentration was also positively correlated with feeding rate and digestive gland indices. Octopus vulgaris held in captivity grew rapidly and consistently and RNA concentrations were lower in bigger animals than in smaller animals. Neither experiment provided direct support for the hypothesis that RNA concentration or the RNA to protein ratio is directly related to growth rate. Systematic variation in protein concentration, e.g. in relation to recent feeding, leads us to suggest that protein concentration (mg/g fresh body weight) is likely to provide a more reliable index than the RNA to protein ratio.

Some observations on the behaviour of adult squids, Loligo forbesi, in captivity

Thirty-four adult individuals of Loligo forbesi (males and females with dorsal mantle lengths from 27–77 cm) were observed in captivity in a 3 m diameter closed sea-water system on Faial Island, Azores. Squids were caught by jigging and were fed with horse mackerel (Trachurus picturatus) and chub mackerel (Scomber japonicus), either alive or dead. The maximum survival was 73 days. Feeding behaviour was dependent upon both the size of prey and its state of preservation;e.g. the squid would eat the head of small fish ( about 35 cm) or a fish poorly preserved. Seventeen chromatic, 9 postural and 6 movement components of body patterns were observed and described. Conspecific interactions considered to be aggression and dominance were observed among males; no such interactions occurred when one male and two females were kept together. Body patterns in relation to relaxation, stress, shock, feeding, locomotion and aggression are also described.

DIET AND FECUNDITY OF COLUMBUS CRABS, PLANES MINUTUS, ASSOCIATED WITH OCEANIC-STAGE LOGGERHEAD SEA TURTLES, CARETTA CARETTA, AND INANIMATE FLOTSAM

Abstract The digestive tract contents of 85 Columbus crabs, Planes minutus, are presented. Crabs were collected from oceanic-stage loggerhead turtles, Carettta caretta, and inanimate flotsam near the Azores. The numbers of eggs carried by ovigerous crabs (n = 28) are also presented. Numbers of eggs between turtle crabs and flotsam crabs were similar. Dietary analysis yielded 11 food types from P. minutus. Crabs from turtles contained a higher diversity of food items than crabs from inanimate flotsam. The diet of P. minutus was composed primarily of neustonic invertebrates and algae—similar to prey items found from oceanic-stage loggerhead turtles in past studies. The types of food consumed by P. minutus suggest that crabs may obtain food by consuming other epibionts, by hunting neuston from their substrate, or by capturing food particles expelled by host turtles.

Biology of Loligo forbesi Steenstrup, 1856 (Mollusca: Cephalopoda) in the Azores: sample composition and maturation of squid caught by jigging

Abstract In the period from November 1990 to March 1992, 1820 squid of the species Loligo forbesi Steenstrup, 1856, from the Azores fishery, were sampled. Males comprised 58.9%, ranging from 240 to 937 mm in dorsal mantle length ( ML ) (mean 590 mm) and 41.1% were females, ranging from 200 to 462 ML (mean 359 mm). Eighty-one percent of the males were sexually mature (mean ML 620.5 mm) and 87.4% of the females (mean ML 365 mm). Three maturity indices for females and for males were applied. Both sexes showed highest maturity values in winter and spring, lowest in autumn, but mature squid were found in all monthly samples. Recruitment into the fishery was higher during autumn.

Plastic ingestion in oceanic-stage loggerhead sea turtles (Caretta caretta) off the North Atlantic subtropical gyre

Juvenile oceanic-stage sea turtles are particularly vulnerable to the increasing quantity of plastic coming into the oceans. In this study, we analysed the gastrointestinal tracts of 24 juvenile oceanic-stage loggerheads (Caretta caretta) collected off the North Atlantic subtropical gyre, in the Azores region, a key feeding ground for juvenile loggerheads. Twenty individuals were found to have ingested marine debris (83%), composed exclusively of plastic items (primarily polyethylene and polypropylene) identified by μ-Fourier Transform Infrared Spectroscopy. Large microplastics (1-5mm) represented 25% of the total number of debris and were found in 58% of the individuals sampled. Average number of items was 15.83±6.09 (±SE) per individual, corresponding to a mean dry mass of 1.07±0.41g. The results of this study demonstrate that plastic pollution acts as another stressor for this critical life stage of loggerhead turtles in the North Atlantic.

Exploitation promotes earlier sex change in a protandrous patellid limpet, Patella aspera Röding, 1798

Abstract Exploitation of organisms can prompt the reduction in the number and size of target populations consequently affecting reproductive output and replenishment. Here, we investigated the effects of exploitation on the population structure of a protandrous patellid limpet, Patella aspera, an overexploited Macaronesian endemic. Timed dives were used to collect animals across eleven islands of Macaronesia. Individuals were inspected for sex, size, and gonad stage. Using catch effort (time per person) per island coastal perimeter as a surrogate for exploitation intensity, we found that limpet abundance (CPUE) and mean size tended to decrease with exploitation intensity. When considering the sex of animals separately, the size of the largest male, but not females, decreased with exploitation. In contrast, the size of the smallest male remained relatively consistent, whereas the size of the smallest female decreased significantly with exploitation. As exploitation is mostly targeting larger individuals, results suggest that males are compensating the removal of larger females, by undergoing sex change at smaller and presumably earlier sizes. These results have wider implications for the conservation of P. aspera, as a reduction in female size will likely affect the numbers of oocytes produced, hence fecundity. Regulations promoting the protection of the larger‐sized animals should be enforced to safeguard the replenishment of the population.

The role of Malcolm Clarke (1930–2013) in the Azores as a scientist and educationist

Malcolm Roy Clarke (1930–2013) was a British teuthologist who made an important contribution to marine science in the Azores archipelago (Portugal). Malcolm started doing research in the Azores from 1980s onward, settling for residency in 2000 after retirement (in 1987). He kept publishing on Azorean cephalopods collaborating in 20% of the peer reviewed works focus- ing on two main areas: dietary studies; and the ecology of cephalopods on seamounts. Since his first visit in 1981, he was involved in the description of the dietary ecology of several cetaceans, seabirds, and large pelagic and deep-water fish. Using his own data, Malcolm revised the association of cephalopods with seamounts, updating and enlarging the different cephalopod groups according to species behaviour and ecology. Malcolm taught several students working in the Azores on cephalopods and beak identification, lecturing the Third International Workshop in Faial (2007). He empowered the recently established research community, by providing important contacts with foreign institutes and informal advice. He collaborated in the regional cetacean stranding network (RACA) and was an active member of the advisory board of the journal Arquipelago—Life and Marine Sciences . But the scientific role of Malcolm Clarke in the Azores went beyond his academic activities. In the last 10 years Malcolm and Dot Clarke dedicated themselves to building and running a museum on Pico Island, showing the biology of the sperm whale and its interaction with squid; a cultural and touristic legacy for future gen- erations to enjoy.