Seasonal patterns of food availability: influences on the reproductive output and body condition of the herbivorous crab Grapsus albolineatus

Kennish, Robin

doi:10.1007/s004420050075

Cited by 65 publications

(58 citation statements)

References 38 publications

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“…Our study also demonstrated that G. salinus and G. tigrinus are capable of foraging different types of food, however, when the filamentous brown alga P. littoralis was present it seemed to be the most important diet of the studied gammarids. The grazing pressure of mesoherbivores changed with season that is consistent to the earlier observations (Duffy and Hay 1994;Kennish 1997;OravKotta and Kotta 2003;Kotta et al 2006). Our study showed statistical differences in the grazing of different macrophytes both in warm (summer) and cold season (autumn).…”

Section: Discussionsupporting

confidence: 92%

Seasonal variability in the grazing potential of the invasive amphipod Gammarus tigrinus and the native amphipod Gammarus salinus (Amphipoda: Crustacea) in the northern Baltic Sea

et al. 2008

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Mesograzers are known to reduce the biomass of their host plant and modify the structure of the whole macrophyte community in many ecosystems. Thus, the introduction of an efficient mesograzer may destabilize macrophyte community and also affect the native grazers. We estimated how large proportion of macrophyte production are consumed by the alien gammarid G. tigrinus and the native gammarid G. salinus in the species poor ecosystem of the northern Baltic Sea. We analysed whether G. tigrinus consumes different diet as the native G. salinus and whether the effect of G. tigrinus on the survival of the native G. salinus is macrophyte species specific. Grazing experiments showed that there was a clear difference in the grazing rates of gammarids among the studied macrophyte species in summer and autumn but not in spring. The grazing rates were significantly higher in the prevailing macrophyte Pilayella littoralis as compared to other macrophytes. The grazing was inversely related to the diurnal net photosynthetic values of macrophytes. The gammarid amphipods potentially removed only a minor part of plant primary production except for summer and autumn when grazing of a few perennial species exceeded macrophyte production. Macrophyte species and presence of G. salinus had no effect on the survival of G. tigrinus. The presence of G. tigrinus, however, reduced the survival of the native gammarids within P. littoralis in summer. To conclude it is likely that both native and alien gammarid amphipods do not exert significant pressure on the macroalgal communities in the northern Baltic Sea. Competitive interactions between G. tigrinus and G. salinus within the prevailing macrophyte P. littoralis is the likely explanation of the decline of the native gammarid amphipods after the establishment of G. tigrinus in the northern Baltic Sea.

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Section: Discussionsupporting

confidence: 92%

Seasonal variability in the grazing potential of the invasive amphipod Gammarus tigrinus and the native amphipod Gammarus salinus (Amphipoda: Crustacea) in the northern Baltic Sea

et al. 2008

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“…This may also mean that the effects of crabs and molluscs would be to crop down any algae that grows from a barren surface. Previous studies on crabs in Hong Kong Kennish 1997) show that these feed preferentially on algal turfs compared to foliose algae such as Ulva and Porphyra. In the study of Kennish et al (1996), faecal analysis revealed that a greater proportion of algal food is consumed in the winter suggesting that the crab digests filamentous algae more efficiently than encrusting algae.…”

Section: B46mentioning

confidence: 95%

“…Turf forming algae first recruits into the encrusting or bare substratum and this is followed by Ulva and Porphyra. The arrival of Ulva precedes the arrival of Porphyra in cage treatments although Porphyra cover became dense during early January up to late that the crab G. albolineatus in these shores are well fed with the more nutritious filamentous and turf forming algae compared to the encrusting algae (Kennish 1996;Kennish et al 1996;Kennish 1997). …”

Section: Percentage Cover In Treatment Plots (Consumer Effects Study)mentioning

confidence: 99%

“…Many previous studies (Williams 1993a(Williams , 1993b(Williams , 1994Kaehler andWilliams 1996, 1997;Hutchinson andWilliams 2001, 2003) involving grazer-alga interaction were already conducted in Hong Kong but no studies on the effects of several consumers using exclusion treatments were previously performed. Studies on crabs were also previously conducted such as on its feeding ecology and its relationships on seasonal variation of relative abundances of algal cover (Kennish et al , 1997. These studies provide us a snapshot of how consumers impact the algal assemblage in these shores but their interactive effects and what particular guilds of consumers have predictably larger impact on these algal assemblages are still unanswered.…”

Section: B46mentioning

confidence: 99%

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Variability and community organization in moderately exposed tropical rocky shore algal communities as influenced by different consumer groups

Macusi

2008

Nat Prec

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Tropical rocky shores have been described as diverse and having a complex variety of consumers. This wide array of consumers has been studied to shed light on the different roles of consumers, particularly grazers on rocky shores and how they affect the relative abundance and distribution of sessile algal prey. One of the aims of ecology is to clarify factors that regulate and structure the abundance, growth and relationship of predators and preys in each habitat. Grazing is known as one of the most important determinants of growth and distribution of rocky shore communities. In this study a comparison between the different effects of fishes, crabs and molluscan herbivores on the relative abundances of microalgae and macroalgae from micro (hundreds of microns) to medium (tens of meters to kilometers) scales of spatial variability was conducted. At the start of the experiment several hypotheses were forwarded: 1) that herbivores will reduce the density of microalgae and macroalgal cover causing a barren appearance and ultimately reducing algal diversity where grazing intensity is highest across treatments, sites and shores; 2) and where grazing pressure is low, algal cover and diversity will be high; 3) and that fishes and crabs contribute significantly to maintaining a high grazing pressure in the area and that fishes control the algal assemblage in benign environments. These were evaluated by exclusion experiments and quadrat counts to determine the effects of grazers on different functional groups of algae. Microalgal density was assessed indirectly by measuring chlorophyll a from rock chips taken from the treatment plots. Microspatial variability of different sites was assessed by scoring digital micrographs of rock chips also taken from treatment plots. Algal cover of treatment plots was assessed by using digital photos taken during forthnightly visits in all sites. The univariate and multivariate results show significant differences across treatments, sites and shores and even significant temporal differences. Microalgal abundance and erect algal cover in fenced plots were significantly different compared to the other treatments. Grazer removal effectively caused a completely different algal assemblage to develop through time in cage and fenced treatments while maintaining a mostly barren cover in most open and control set-ups. Species which are not typically present in shores have grown inside cage and fenced treatments during the period of manipulation. Molluscan herbivores are the most effective grazers in these shores and control the relative distribution of algae by restricting the recruitment success of algal sporelings particularly erect macroalgae. Herbivorous fishes and crabs do not directly influence algal sporelings since the early stages of algae are too small for them to handle. But both consumers complement the removal of turf forming algae. The observed over all grazing effects show that molluscs have greater impact than fishes and crabs combined; the effect of either fishes or crabs are equal. Hence, the impact of crabs and fishes on these shores are minimal, mainly affecting turf forming algae. Moreover, the observed spatial variability in algal assemblage from micro to medium scales is mainly driven by high grazing intensity. Thus, grazing acts as a highly effective top down control mechanism in these shores during the cool winter season.

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“…The feeding habit is not specialized and is an important factor for the success of invasion and establishment in new environments. It has been reported that many grapsoid crabs are also herbivores or omnivores in wetland ecosystems (Buck et al 2003, Frantini et al 2000, Kennish 1997, Ólafsson et al 2002, Puccio 2006, Skilleter & Anderson 1986, Smith et al 1989; for a review, Wolcott & O'Connor 1992) and facilitate the circulation of organic matter and energy flow in the tropical and temperate area (Camilleri 1989, Emmerson & McGwynne 1992, Levinton & Lopez 1977, Werry & Lee 2005). The omnivorous and detrital feeding habit common among the grapsoid species along with its wide salinity tolerance and migratory abilities (Kobayashi 2003) are also important factors for E. japonica to maintain populations in a wide range of environments.…”

Section: Ecological Niche Of Eriocheir Japonicamentioning

confidence: 99%

Dietary preferences of the Japanese mitten crab Eriocheir japonica in a river and adjacent seacoast in north Kyushu, Japan

Kobayashi¹

2009

Plankton Benthos Res

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Abstract:The diet of the Japanese mitten crab Eriocheir japonica was investigated by examining the stomach contents of middle-and large-sized crabs (carapace width Ͼ10 mm). Crabs were collected in the freshwater area (growth area), tidal river, and seacoast area (reproductive area) of the Saigo River, Fukuoka Prefecture, Japan. Analysis of the diet of E. japonica was carried out using the frequency of occurrence and percentage point methods. The stomach contents were classified into 4 large and 27 small categories. It was evident that E. japonica was an omnivore and a deposit feeder, mainly feeding on the detritus derived from vascular plants growing along the river channel. Filamentous algae Cladophora sp., aquatic insects (e.g., Chironomidae), sediments such as mud or sand, and artificial products such as plastic or yarn were often found, suggesting that E. japonica mainly feeds on detritus lying on the substrate without sorting well. Stomach contents of adult crabs in the tidal area exhibited higher frequency of animal materials (i.e., fish, gastropods, and crabs) than those of young and adult crabs in the freshwater area, suggesting that adult crabs in the tidal area eat more animal materials. Such an omnivorous feeding habit is similar to other related brachyuran crabs (grapsoidae) and may be one of the important factors which enables E. japonica's wide distribution along the river and seacoast.

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Seasonal patterns of food availability: influences on the reproductive output and body condition of the herbivorous crab Grapsus albolineatus

Cited by 65 publications

References 38 publications

Seasonal variability in the grazing potential of the invasive amphipod Gammarus tigrinus and the native amphipod Gammarus salinus (Amphipoda: Crustacea) in the northern Baltic Sea

Seasonal variability in the grazing potential of the invasive amphipod Gammarus tigrinus and the native amphipod Gammarus salinus (Amphipoda: Crustacea) in the northern Baltic Sea

Variability and community organization in moderately exposed tropical rocky shore algal communities as influenced by different consumer groups

Dietary preferences of the Japanese mitten crab Eriocheir japonica in a river and adjacent seacoast in north Kyushu, Japan

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