Influence of conspecifics on the ontogenetic habitat shift of juvenile Caribbean spiny lobsters

2001 ◽  
Vol 52 (8) ◽  
pp. 1077 ◽  
Author(s):  
Michael J. Childress ◽  
William F. Herrnkind

Werner and Gilliam’s (1984) model predicts that size-specific rates of growth and mortality determine the size at transition for animals with an ontogenetic habitat shift (OHS). Although animals are unlikely to calculate mortality rate, they often respond to changes in predation risk. For many social species, an individual’s risk of predation is reduced by conspecific aggregation. We hypothesize that individuals in groups respond to this reduction of predation risk and should shift habitats at a smaller size than solitary individuals. We tested this hypothesis by altering food availability, predation risk and conspecific presence for newly settled spiny lobsters in mesocosms. Juvenile Caribbean spiny lobsters, Panulirus argus, undergo an ontogenetic habitat shift from algal dwelling to crevice sheltering concomitant with aggregation in crevices. We found that juveniles raised with low food availability and low predation risk underwent transition at a smaller size. We also found that juveniles raised with conspecifics underwent transition at a smaller size than did solitary lobsters under the same conditions. Our results suggest that the ontogenetic habitat shift of algal-phase lobsters is accelerated when food is scarce, predation risk is low, and conspecifics are present. In the absence of conspecifics, algal lobsters wait until they are larger to change from algal dwelling to crevice sheltering. This result suggests that ontogenetic habitat shifts for gregarious animals are influenced by the proximity of conspecifics.

2013 ◽  
Vol 71 (4) ◽  
pp. 909-917 ◽  
Author(s):  
Christian Jørgensen ◽  
Anders Frugård Opdal ◽  
Øyvind Fiksen

Abstract Since the classical works by Hjort linked the survival of early life stages of fish to year-class strength and recruitment, fisheries science has struggled to understand the fate of fish eggs and larvae. Here we discuss how food availability will influence growth and survival of larvae when foraging behaviour is flexible and involves predation risk. We use theory to show that small larval fish with a high risk of predation should nevertheless forage intensely and maintain high growth rates. The implication of this is that food availability is more important to recruitment success than is often assumed from studies of growth rate, since the main effect of low food availability appears as increased predation rates. As larvae develop and grow bigger, they are expected to tailor their behaviour to balance food intake and predation risk, which makes it more probable that environmental fluctuations will cause growth differences. A theoretical framework including larval behaviour thus illustrates how several existing hypotheses, i.e. “bigger is better”, “stage duration”, and “growth-selective predation”, emphasize different aspects of larval success but can be understood more generally and coherently when interpreted in the light of behavioural trade-offs. This may lead to more consistent consideration of larval behaviour in biophysical models of fish recruitment.


Crustaceana ◽  
2015 ◽  
Vol 88 (7-8) ◽  
pp. 839-856 ◽  
Author(s):  
J. Hesse ◽  
J. A. Stanley ◽  
A. G. Jeffs

Kelp habitats are in decline in many temperate coastal regions of the world due to climate change and expansion of populations of grazing urchins. The loss of kelp habitat may influence the vulnerability to predators of the juveniles of commercially important species. In this study relative predation rates for kelp versus barren reef habitat were measured for early juvenile Australasian spiny lobster, Jasus edwardsii (Hutton, 1875), on the northeastern coast of New Zealand using tethering methods. Variation in assemblages of predators over small spatial scales appeared to be more important for determining the relative predation of lobsters, regardless of habitat type. Therefore, the assessment of relative predation risk to early juvenile lobsters between kelp and barren habitats will require more extensive sampling at a small spatial scale, as well as a specific focus on sampling during crepuscular and nocturnal periods when these lobsters are most at risk of predation.


2010 ◽  
Vol 37 (4) ◽  
pp. 273 ◽  
Author(s):  
Karen Fey ◽  
Peter B. Banks ◽  
Hannu Ylönen ◽  
Erkki Korpimäki

Context. Potential mammalian prey commonly use the odours of their co-evolved predators to manage their risks of predation. But when the risk comes from an unknown source of predation, odours might not be perceived as dangerous, and anti-predator responses may fail, except possibly if the alien predator is of the same archetype as a native predator. Aims. In the present study we examined anti-predator behavioural responses of voles from the outer archipelagos of the Baltic Sea, south-western Finland, where they have had no resident mammalian predators in recent history. Methods. We investigated responses of field voles (Microtus agrestis) to odours of native least weasels (Mustela nivalis) and a recently invading alien predator, the American mink (Mustela vison), in laboratory. We also studied the short-term responses of free-ranging field voles and bank voles (Myodes glareolus) to simulated predation risk by alien mink on small islands in the outer archipelago of the Baltic Sea. Key results. In the laboratory, voles avoided odour cues of native weasel but not of alien mink. It is possible that the response to mink is a context dependent learned response which could not be induced in the laboratory, whereas the response to weasel is innate. In the field, however, voles reduced activity during their normal peak-activity times at night as a response to simulated alien-mink predation risk. No other shifts in space use or activity in safer microhabitats or denser vegetation were apparent. Conclusions. Voles appeared to recognise alien minks as predators from their odours in the wild. However, reduction in activity is likely to be only a short-term immediate response to mink presence, which is augmented by longer-term strategies of habitat shift. Because alien mink still strongly suppresses vole dynamics despite these anti-predator responses, we suggest that behavioural naiveté may be the primary factor in the impact of an alien predator on native prey. Implications. Prey naiveté has long been considered as the root cause of the devastating impacts of alien predators, whereby native prey simply fail to recognise and respond to the novel predation risk. Our results reveal a more complex form of naiveté whereby native prey appeared to recognise alien predators as a threat but their response is ultimately inadequate. Thus, recognition alone is unlikely to afford protection for native prey from alien-predator impacts. Thus, management strategies that, for example, train prey in recognition of novel threats must induce effective responses if they are expected to succeed.


2015 ◽  
Vol 72 (suppl_1) ◽  
pp. i177-i184 ◽  
Author(s):  
Benjamin C. Gutzler ◽  
Mark J. Butler ◽  
Donald C. Behringer

Abstract Casitas are artificial shelters used by fishers to aggregate Caribbean spiny lobsters (Panulirus argus) for ease of capture. However, casitas may function as an ecological trap for juvenile lobsters if they are attracted to casitas and their growth or mortality is poorer compared with natural shelters. We hypothesized that juvenile lobsters may be at particular risk if attracted to casitas because they are less able than larger individuals to defend themselves, and do not forage far from shelter. We compared the nutritional condition, relative mortality, and activity of lobsters of various sizes in casitas and natural shelters in adult and juvenile lobster-dominated habitats in the Florida Keys (United States). We found that the ecological effects of casitas are complex and location-dependent. Lobsters collected from casitas and natural shelters did not differ in nutritional condition. However, juvenile lobsters in casitas experienced higher rates of mortality than did individuals in natural shelters; the mortality of large lobsters did not differ between casitas and natural shelters. Thus, casitas only function as ecological traps when deployed in nursery habitats where juvenile lobsters are lured by conspecifics to casitas where their risk of predation is higher. These results highlight the importance of accounting for animal size and location-dependent effects when considering the consequences of habitat modification for fisheries enhancement.


2010 ◽  
Vol 76 (4) ◽  
pp. 348-353 ◽  
Author(s):  
A. A. Robson ◽  
C. Garcia De Leaniz ◽  
R. P. Wilson ◽  
L. G. Halsey

2018 ◽  
Vol 11 (1) ◽  
pp. 100-103
Author(s):  
Aldo Alvarez-Risco ◽  
Jaime Delgado-Zegarra ◽  
Jaime A. Yáñez ◽  
Santiago Diaz-Risco ◽  
Shyla Del-Aguila-Arcentales

Abstract The growth of tourism to Peru and the gastronomic boom with millions of people looking to taste Peruvian food is resulting in a risk of predation of natural sources necessary to make these dishes. The focus in only obtaining these ingredients can generate significant damage to the Peruvian biodiversity, so stakeholders need to develop strategies to avoid predation due to the gastronomic boom. Citizens and visitors need to play a role in protecting the natural resources and contributing to environmental sustainability.


1998 ◽  
Vol 55 (2) ◽  
pp. 387-396 ◽  
Author(s):  
Nathan P Nibbelink ◽  
Stephen R Carpenter

Habitat structure alters food availability and predation risk, thereby directly affecting growth, mortality, and size structure of fish populations. Size structure has often been used to infer patterns of resource abundance and predation. However, food availability and predation risk in contrasting habitats have proven difficult to measure in the field. We use an inverse modeling approach to estimate food availability and habitat choice parameters from changes in length distributions of bluegill (Lepomis macrochirus). The model suggests that dynamics of bluegill length distributions primarily reflect food availability and habitat choice. Bluegill behavior minimized effects of size-selective predation on size structure. Parameters for food availability and habitat choice were correlated. It was therefore not possible to attain unique estimates of food availability and habitat selection when both were free parameters. However, when one parameter was estimated independently, the other could be identified. In five Wisconsin lakes, seining studies were used to estimate the size at which bluegill switched from littoral to pelagic habitats. Using this measure of switch size in the model, we estimated food availability for bluegill in each lake. These estimates were positively correlated with observed growth (r2 = 0.91), demonstrating the model's ability to estimate food availability.


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Felipe A Briceño ◽  
Quinn P Fitzgibbon ◽  
Elias T Polymeropoulos ◽  
Iván A Hinojosa ◽  
Gretta T Pecl

Abstract Predation risk can strongly shape prey ecological traits, with specific anti-predator responses displayed to reduce encounters with predators. Key environmental drivers, such as temperature, can profoundly modulate prey energetic costs in ectotherms, although we currently lack knowledge of how both temperature and predation risk can challenge prey physiology and ecology. Such uncertainties in predator–prey interactions are particularly relevant for marine regions experiencing rapid environmental changes due to climate change. Using the octopus (Octopus maorum)–spiny lobster (Jasus edwardsii) interaction as a predator–prey model, we examined different metabolic traits of sub adult spiny lobsters under predation risk in combination with two thermal scenarios: ‘current’ (20°C) and ‘warming’ (23°C), based on projections of sea-surface temperature under climate change. We examined lobster standard metabolic rates to define the energetic requirements at specific temperatures. Routine metabolic rates (RMRs) within a respirometer were used as a proxy of lobster activity during night and day time, and active metabolic rates, aerobic scope and excess post-exercise oxygen consumption were used to assess the energetic costs associated with escape responses (i.e. tail-flipping) in both thermal scenarios. Lobster standard metabolic rate increased at 23°C, suggesting an elevated energetic requirement (39%) compared to 20°C. Unthreatened lobsters displayed a strong circadian pattern in RMR with higher rates during the night compared with the day, which were strongly magnified at 23°C. Once exposed to predation risk, lobsters at 20°C quickly reduced their RMR by ~29%, suggesting an immobility or ‘freezing’ response to avoid predators. Conversely, lobsters acclimated to 23°C did not display such an anti-predator response. These findings suggest that warmer temperatures may induce a change to the typical immobility predation risk response of lobsters. It is hypothesized that heightened energetic maintenance requirements at higher temperatures may act to override the normal predator-risk responses under climate-change scenarios.


Mammalia ◽  
2015 ◽  
Vol 79 (4) ◽  
Author(s):  
Roberta Chirichella ◽  
Andrea Mustoni ◽  
Marco Apollonio

AbstractIn large mammalian herbivores, an increase in herd size not only reduces predation risk but also energy intake. As a consequence, the size of the groups made up by herbivores is often assumed to be the outcome of a trade-off depending on local predation risk and food availability. We studied Alpine chamois (


2016 ◽  
Vol 67 (8) ◽  
pp. 1153 ◽  
Author(s):  
Amalia M. Harrington ◽  
Kevin A. Hovel

Spiny lobsters use refuge habitat and gregarious behaviour to reduce predation risk, particularly in their vulnerable juvenile and subadult stages. We characterised patterns of sheltering behaviour in the California spiny lobster (Panulirus interruptus (Randall)) on southern California rocky reefs and used manipulative experiments to examine how these behaviours affect the survival of subadult lobsters and shelter selection. Lobsters generally were gregarious and subadults were commonly found inhabiting shelters with adult lobsters. Tethering experiments with subadults indicated that communal denning increases the odds of survival only when adult lobsters are part of aggregations. This corresponded to results from a shelter choice experiment in the laboratory, where the presence of predators caused subadults to shelter more often with adult conspecifics rather than other subadults. Despite the gregarious nature of P. interruptus, solitary subadults were common at all sites. Although field experiments clearly indicated that solitary lobsters increased their odds of survival by inhabiting shelters scaled to body size, evidence that lobsters exhibit shelter scaling on natural reefs was mixed. Our results indicate that subadult P. interruptus exhibit similar behavioural strategies as other spiny lobsters to reduce predation risk, and they provide a more comprehensive examination of P. interruptus behaviour than previously available.


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