Factors affecting distribution of freshwater shrimps and prawns in the Hiwasa River, southern central Japan

Saito, Minoru; Yamashiro, Tadashi; Hamano, Tatsuo; Nakata, Kazuyoshi

doi:10.18353/crustacea.41.0_27

Cited by 16 publications

(14 citation statements)

References 28 publications

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“…Large adult crabs are usually found in the upper regions of relatively long rivers (Kobayashi and Matsuura, 1991;Saito et al, 2012). The meaning of the size variation in each basin can be different between adult and juvenile stages.…”

Section: Discussionmentioning

confidence: 99%

Selectivity of Two Methods for Surveying the Japanese Mitten Crab, Eriocheir Japonica (De Haan, 1835), in a Riverine Environment

Kobayashi¹,

Vazquez-Archdale

2016

Journal of Crustacean Biology

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A B S T R A C TDifferences between the results of pot fishing and hand-net collecting of the Japanese mitten crab, Eriocheir japonica (De Haan, 1835), were examined to increase the accuracy of sampling natural population in freshwater and tidal areas of a small river. Large adult crabs were caught in pots; small juveniles mostly collected with the hand nets. The difference in size composition in the freshwater river is probably caused by changes in the dietary preferences and behaviors that occur as crabs grow larger. The sex ratio was strongly male-biased in pot fishing in the tidal river in contrast to hand-net collecting (no bias), and males captured in the pots were slightly larger than those caught by hand-nets. The sex ratio bias observed in pot fishing in the tidal river can be explained by mating behavior, whereas the differences in the size of males between the two methods can be explained by the dimorphism and alternative mating strategy of male E. japonica. The proportions of ovigerous females in the tidal river in early winter were larger in pot than in hand-net samples. Differences in the proportion of ovigerous females between the two gears in the tidal river may have resulted from the presence of two groups differing in reproductive season and the wandering activities of ovigerous and non-ovigerous females. Although pot fishing is useful for studying reproductive ecology, the resulting data is sometimes strongly biased. In contrast, hand-net collecting is essential for gathering a complete range of crabs from all size classes and the data generated by this method is more representative of their distribution pattern. It is necessary to make up for the shortcoming of each sampling method.

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Section: Discussionmentioning

confidence: 99%

Selectivity of Two Methods for Surveying the Japanese Mitten Crab, Eriocheir Japonica (De Haan, 1835), in a Riverine Environment

Kobayashi¹,

Vazquez-Archdale

2016

Journal of Crustacean Biology

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“…Toyota & Seki, 2014) are available. Target species could be extended to crabs, smaller Atyidae shrimps (Saito et al, 2012), and possibly to crayfish inhabiting clear water streams. Further work comparing detection probability between different channel units (riffle, run and pool), or testing accuracy of species identification in conspicuous pairs of species (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…This clear water stream has no dams and an abundant crustacean fauna. Details of this river and the experimental site can be found in Saito et al (2012). Macrobrachium shrimps inhabiting this river are M. formosense Bate, 1868 andM.…”

Section: Experimental Sitementioning

confidence: 99%

“…Macrobrachium shrimps inhabiting this river are M. formosense Bate, 1868 andM. japonicum (De Haan, 1849) (Hamano et al, 2000;Saito et al, 2012), both of which are amphidromous.…”

Section: Experimental Sitementioning

confidence: 99%

“…Underwater movie recording has been found effective for studying fish assemblages in marine environment especially the coral reefs (Cappo et al, 2003;Pelletier et al, 2011), where low turbidity and use of SCUVA gears allow deployment of recording equipment. In freshwater environment, Saito et al (2012) used this method alongside contemporary sweeping and bait trapping to compare the relative abundance of freshwater shrimps and crabs in macrohabitat analyses. This technique could also be deployed for quantitative abundance estimation, if the sampling effort was quantified with the sampled area instead of sampled time.…”

Section: Introductionmentioning

confidence: 99%

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Validity of movie recording for quantitative abundance estimation and body size measurement of <i>Macrobrachium</i> shrimps

2015

Self Cite

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Collecting Macrobrachium shrimps for abundance estimation is challenging, especially in high gradient, boulder dominated streams. The recent advent of digital cameras could change the situation by enabling previously under-used snorkel counting to yield verifiable data. The validity and efficiency of underwater movie recording for shrimp census were tested and compared with those of underwater shrimp net collection and sweeping in a field experiment (1-4 adult shrimps/m 2 ). Total length estimates from the video footage were compared with caliper measurements. Detection was not affected by species, sex, or shrimp density. Movie recording and shrimp net collection yielded high and constant detection probability of adult shrimps (0.955 and 0.874), in contrast to sweeping (0.097). The movie recording had higher efficiency than the other two methods. For juveniles, only shrimp net collection was valid as an abundance indicator, with a detection probability of 0.338. Accuracy of total length estimates made from the video footage did not differ between species or sex and was highly correlated with the actual measurements by digital caliper. These results confirm that in adult Macrobrachium shrimps, the movie recording is valid for body size and quantitative abundance estimation, but not in juveniles.

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Direct and indirect effects of amphidromous shrimps on nutrient mineralization in streams in Japan

et al. 2022

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Animals effect element cycling in ecosystems by consumption and excretion. Amphidromous shrimps frequently dominate low-mid altitude streams, where downstream connectivity to oceans is sustained.Although shrimps' direct influence on benthic communities has been studied, little is known about their influences on nutrient cycling. Here, we hypothesized that the dominance of shrimps alters nutrient mineralization by benthic macroinvertebrates in streams due to the difference in the quality and quantity of excretion between shrimps and aquatic insects. We tested this hypothesis through a field manipulative experiment, excretion measurements of animals, and field surveys. In the field manipulative experiment, the presence of shrimps slightly decreased the biomass of aquatic insects but tripled total benthic macroinvertebrate biomass directly through their own biomass. The massspecific NH4 + excretion rate by shrimps was similar to aquatic insects, and the areal NH4 + excretion by benthic macroinvertebrates was increased by 2.5 times in the presence of shrimps. In contrast, shrimps excreted significantly less soluble reactive phosphorus (SRP) than aquatic insects, and the presence of shrimps did not affect areal SRP excretion by benthic macroinvertebrates. The field survey showed a positive correlation of NO3 − concentration with the shrimp density, inferring the excess NH4 + was A Self-archived copy in Kyoto University Research Information Repository https://repository.kulib.kyoto-u.ac.jp nitrified. Although the nutrient concentration of stream water is frequently attributed to watershed conditions, the results of this study indicate that downstream connectivity to oceans may also influence nutrient dynamics of the stream through the density of amphidromous shrimps.

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Factors affecting distribution of freshwater shrimps and prawns in the Hiwasa River, southern central Japan

Cited by 16 publications

References 28 publications

Selectivity of Two Methods for Surveying the Japanese Mitten Crab, Eriocheir Japonica (De Haan, 1835), in a Riverine Environment

Selectivity of Two Methods for Surveying the Japanese Mitten Crab, Eriocheir Japonica (De Haan, 1835), in a Riverine Environment

Validity of movie recording for quantitative abundance estimation and body size measurement of <i>Macrobrachium</i> shrimps

Direct and indirect effects of amphidromous shrimps on nutrient mineralization in streams in Japan

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