Atema Jelle

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  • Article
    Effects of prior experience on shelter-seeking behavior of juvenile American lobsters
    (University of Chicago, 2017-05-24) Bayer, Skylar R. ; Bianchi, Katherine M. ; Atema, Jelle ; Jacobs, Molly W.
    Shelter-seeking behaviors are vital for survival for a range of juvenile benthic organisms. These behaviors may be innate or they may be affected by prior experience. After hatching, American lobsters Homarus americanus likely first come into contact with shelter during the late postlarval (decapodid) stage, known as stage IV. After the subsequent molt to the first juvenile stage (stage V), they are entirely benthic and are thought to be highly cryptic. We hypothesized that postlarval (stage IV) experience with shelter would carry over into the first juvenile stage (stage V) and reduce the time needed for juveniles to locate and enter shelters (sheltering). We found some evidence of a carryover effect, but not the one we predicted: stage V juveniles with postlarval shelter experience took significantly longer to initiate sheltering. We also hypothesized that stage V juveniles would demonstrate learning by relocating shelters more quickly with immediate prior experience. Our findings were mixed. In a maze, juveniles with immediate prior experience were faster to regain visual contact with shelter, suggesting that they had learned the location of the shelter. In contrast, there was no significant effect of immediate prior experience on time to initiate sheltering in an open arena, or in the maze after juveniles had regained visual contact. We conclude that very young (stage V) juvenile lobsters modify their shelter-seeking behavior based on prior experiences across several timescales. Ecologically relevant variation in habitat exposure among postlarval and early juvenile lobsters may influence successful recruitment in this culturally and commercially important fishery species.
  • Article
    Sound detection by the American lobster (Homarus americanus)
    (The Company of Biologists, 2021-03-25) Jézéquel, Youenn ; Jones, Ian T. ; Bonnel, Julien ; Chauvaud, Laurent ; Atema, Jelle ; Mooney, T. Aran
    Although many crustaceans produce sounds, their hearing abilities and mechanisms are poorly understood, leaving uncertainties regarding whether or how these animals use sound for acoustic communication. Marine invertebrates lack gas-filled organs required for sound pressure detection, but some of them are known to be sensitive to particle motion. Here, we examined whether the American lobster (Homarus americanus) could detect sound and subsequently sought to discern the auditory mechanisms. Acoustic stimuli responses were measured using auditory evoked potential (AEP) methods. Neurophysiological responses were obtained from the brain using tone pips between 80 and 250 Hz, with best sensitivity at 80–120 Hz. There were no significant differences between the auditory thresholds of males and females. Repeated controls (recordings from deceased lobsters, moving electrodes away from the brain and reducing seawater temperature) indicated the evoked potentials' neuronal origin. In addition, AEP responses were similar before and after antennules (including statocysts) were ablated, demonstrating that the statocysts, a long-proposed auditory structure in crustaceans, are not the sensory organs responsible for lobster sound detection. However, AEPs could be eliminated (or highly reduced) after immobilizing hairfans, which cover much of lobster bodies. These results suggest that these external cuticular hairs are likely to be responsible for sound detection, and imply that hearing is mechanistically possible in a wider array of invertebrates than previously considered. Because the lobsters' hearing range encompasses the fundamental frequency of their buzzing sounds, it is likely that they use sound for intraspecific communication, broadening our understanding of the sensory ecology of this commercially vital species. The lobsters' low-frequency acoustic sensitivity also underscores clear concerns about the potential impacts of anthropogenic noise.
  • Preprint
    Planktonic Larval Duration, age and growth of Ostorhinchus doederleini (Pisces: Apogonidae) on the southern Great Barrier Reef, Australia
    ( 2013-09-15) Kingsford, Michael J. ; Finn, M. D. ; O’Callaghan, M. D. ; Atema, Jelle ; Gerlach, Gabriele
    Cardinalfishes (Apogonidae) are abundant on corals reefs, but there are few data on demography to understand trophodynamics and population dynamics. Ostorhinchus doederleini is a small and abundant apogonid on the Great Barrier Reef (GBR) and throughout the Western Pacific Ocean. We present key demographic parameters for the entire life history from the southern GBR. Daily deposition of increments in otoliths was validated. Fish had a Planktonic Larval Duration (PLD) of 16 to 26 days. PLD was established from fish collected immediately prior to settlement as no settlement mark was found. Fish grew at about 0.35 mm d-1 for the first 20 d after settlement. Fish reached a maximum standard length at about 200 d and no fish lived longer than 368 d at four reefs separated by kilometers to tens of kilometres. There was no evidence for differences in size at age between sexes. Mortality was very high, for fish greater than 60 days old mortality ratesranged from 2.9 to 4.6% per day. Short lives and high mortality rates makes O. doederleini, and potentially other apogonids, vulnerable to recruitment failure. Here we review data on the demographic characteristics of other reef fishes. Although some taxa live to over 50 years, the short lives of apogonids are most aligned with the Gobiidae and Blenniidae (i.e. typically < 1.5 years). Descriptions of fish size, age, longevity, growth and mortality; from hatching to age maxima are very rare for most taxa, even at the level of family.
  • Technical Report
    Behavior of lobsters (Homarus americanus) in a semi-natural environment at ambient temperatures and under thermal stress
    (Woods Hole Oceanographic Institution, 1975-10) Stein, Lauren ; Jacobson, Stewart ; Atema, Jelle
    In January, 1974 we established semi-natural habitats in two 10ft. diameter, octagonal aquaria, with five lobsters (Homarus americanus) each, and several Cancer irroratus, Anguilla rostrata, Pseudopleuronectes americanus and Tautoglabrus adspersus. The lobsters, with respect to size and sex, were identical as possible between tanks, as were the numbers of other species. The aquaria, which received ambient seawater, were arranged identically with an oyster shell substrate, and cement blocks, rocks and ceramic pipes to provide a surplus of shelters. Observations, spanning from February through August, were made both during the day, following feeding, and (using red light) just after sunset, when lobsters are active under natural conditions. Types of behavior we were able to quantify included occupation of specific shelters, feeding, activity and social behavior. In our large aquaria the lobsters appeared to be much less aggressive than generally has been reported. Aggression was most frequent during feeding. Observations at night revealed few encounters, and these were usually either one sided avoidance without pursuit, or mutual ritualized displays. Neither an animal's size nor sex seemed to determine its relative dominance. Dominance shifted somewhat between different animals during the study, and complicating this picture was possible territorial behavior in the larger individuals. In one tank, only the two adult females were territorial from February through mid May, following which no lobster showed stability of residence. In the second tank, only one animal, a female, was territorial for more than several weeks, until early June, when the largest male established a reproductive territory lasting until the end of August. Even in our large aquaria space may have been too limited for all animals to be territorial. Lobsters appeared to lose their position in the hierarchy just prior for up to a month or more following the molt. Such animals were often observed on top of shelters, in exposed locations, where other lobsters apparently did not harass them. Although captive lobsters are considered quite cannibalistic, we lost only one animal, a juvenile female, out of six molts. In our large aquaria, female lobsters about to molt sought out, took up residence, and actively courted the tank's largest male. The males were very non-aggressive toward these females, and yet during this period made violent attacks against other males as well as fish. In each case following mating, the males retired to the shelter and fed on the cast shell. Cohabitation, in or around the males' residences, continued for several days following mating. Diurnal activity, which was evoked by the presence of food, showed little change over the range of 5-28°C. Nocturnal activity, vihich was more spontaneous, was similar in both tanks through mid June (temp. range 5-18°C). The level of activity was as high in late February - early March as in late May, with a dip in activity in late March - late April, a period marked by storms. From mid June on, the nocturnal activity in tank I increased with the increasing temperature, leveling off approximately vihen the peak temperature of 28°C was reached. In contrast, activity in tank II did not increase at temperatures above 20°C, and remained at a much lower level than in tank I. Although patterns of residence and dominance in the lobsters changed seasonally, the direction of change was rather different in each tank and did not seem correlated with temperature. Other factors, such as molting and loss of dominance prior to mating in previously aggressive females, were probably more important than temperature effects. The frequency of temperature range 22-28°C was similar to levels at ambient temperatures. Interspecific relations between lobsters and the other species were mainly pacific, although predation on Cancer by Hi. americanus may have occurred. The response of the eels (Anguilla rostrata) to temperature increases was consistent between tanks. Swimming was first observed at 8°C, and feeding at 10°C. Further, the eels in both tanks became markedly aggressive when the temperature reached 26°C.