Spatial distribution patterns of the sponge-dwelling gnathiid isopod Elaphognathia cornigera (Nunomura) on an intertidal rocky shore of the Izu Peninsula, southern Japan

Tanaka, Katsuhiko; Aoki, Masakazu

doi:10.18353/crustacea.28.0_160

Cited by 13 publications

(8 citation statements)

References 10 publications

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“…Therefore, the first and second instars of C. calva may utilize unknown habitats, and the third instars were thought to penetrate small hexactinellids to reproduce after the final ectoparasitism (Wägele 1988). In E. cornigera in Japan, all three larval instars and adults were observed in a demosponge Halichondria okadai (Kadota) (Tanaka & Aoki 1999). However, the larvae and adults showed different vertical distributions: larvae tended to concentrate in sponges near the mean tidal level but no apparent vertical distribution was observed in adults.…”

Section: Differences In the Benthic Distribution Among Life Stagesmentioning

confidence: 99%

Life history of gnathiid isopods-current knowledge and future directions

Tanaka

2007

Plankton Benthos Res

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Gnathiidae is a family of Isopoda, showing a distinct morphology and ecology. Species in the family have ten walking legs compared to 14 for isopods in general. The life cycle of the Gnathiidae is biphasic including a fish-parasitic larval phase and a non-feeding adult phase, whereas most other isopods have a monophasic life cycle with directdeveloping young similar to adults in morphology and ecology. Although the ecological information on gnathiids has been described fragmentally, studies on the life cycles and population biology have increased dramatically since the 1980's. Larval biology including the host species, emergence pattern and predation risks during parasitism have also been studied from the view of fish disease and symbiotic interactions among fishes. Some authors reported the utilization patterns of benthic substrata and harem formation of adults therein. However, the ecological knowledge of gnathiids is based on a limited number of species of which the benthic habitats are known. Studies rarely identify larvae because of the lack, or insufficiency, of the taxonomic description of larvae of most species. The difficulty in identifying larvae has prevented detailed examination of ectoparasitic behaviour. Furthermore, gnathiid larvae emerging from the benthos or attaching to hosts have been investigated separately from benthic individuals. More efforts on taxonomy and the classification of larvae are necessary to elucidate the larval ecology and the integration of larval and adult biology.

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Section: Differences In the Benthic Distribution Among Life Stagesmentioning

confidence: 99%

Life history of gnathiid isopods-current knowledge and future directions

Tanaka

2007

Plankton Benthos Res

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“…Accordingly, studies within these areas are difficult to conduct. The ecological data currently available on intertidal gnathiids have been extrapolated mainly from studies on a closely related genus, Elaphognathia (Tanaka & Aoki, 1998, 1999), as well as gnathiid taxonomy (Smit et al ., 2002; Hadfield et al ., 2008), life cycle (Smit et al ., 2003; Hadfield et al ., 2009), and fish blood haemogregarine studies (Davies & Smit, 2001; Davies et al ., 2004). From studies examining the distribution of Elaphognathia , we know that the density of Elaphognathiid larvae is greatest at the midpoint between high and low tide, and the overall distribution of Elaphognathiids spans the entire distribution of their sponge habitat, and they are observed throughout the year (Tanaka & Aoki, 1998; Tanaka & Aoki, 1999).…”

Section: Introductionmentioning

confidence: 99%

Diurnal activity patterns of the temporary fish ectoparasite,Gnathia africanaBarnard, 1914 (Isopoda, Gnathiidae), from the southern coast of South Africa

2017

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Gnathiid isopods are one of the most common fish ectoparasites, and are found in both temperate and tropical oceans. On coral reefs, gnathiids are most active at dusk and dawn, and contribute significantly to trophic dynamics, as they are a prey resource for cleaner fish and parasitize numerous fishes. Gnathiids also inhabit temperate intertidal waters, but their activity patterns and contribution to intertidal trophic dynamics remain unstudied. To provide the first ecological data on temperate intertidal gnathiid activity patterns, 172 gnathiid-free Clinus superciliosus were set in an intertidal system in Tsitsikamma National Park, South Africa, during early morning, morning, afternoon, early evening, and evening, high and low tide, and within the inter-and infra-tidal zone to examine gnathiid infestation levels. After exposure, gnathiids from each fish were identified to the species level, counted, and their developmental stage was recorded. All gnathiids were identified as Gnathiia africana. On average, 1 + 5SD gnathiids were collected from each fish, and the majority of gnathiids collected were stage 1. Significantly more gnathiids were collected during morning and afternoon compared with all other time periods. The number of gnathiids collected was not influenced by the fish's exposure to high or low tide, or placement within the tide zone. Although G. africana is free from cleaner fish predation because cleaner fish do not reside in temperate intertidal habitat, G. africana abundance is surprisingly small. Future studies should examine what regulates G. africana population size and the role they play in temperate intertidal food webs.

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“…These isopods are copious in coral reefs and found to be the common external parasites on coral reef fish (Grutter et al 2000). They are found in the intertidal regions in the oceans (Tanaka and Aoki 1999) and to abyssal depths (Cohen and Poore 1994). The Isopoda family Gnathiidae includes about 200 species belonging to 12 genera (Schotte et al 2008 onwards).…”

Section: Introductionmentioning

confidence: 99%

First record of Gnathia sp. an ectoparasitic isopod isolated from the coral reef fish, Heniochus acuminatus collected from the Gulf of Mannar region, southeast coast of India

et al. 2016

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An ectoparasitic isopod, Gnathia sp. was found in the Gill chambers of Heniochus acuminatus collected from the Gulf of Mannar region, Southeast coast of India. The present study signifies the new record of Gnathia sp. an coral reef ectoparasitic isopod captured from the gill net during October 2014. Among the 36 specimens examined 5 specimens were infested with Pranzia larvae of Gnathia sp. The size of the isopods were ranged from 1.5 to 3.2 mm and the host fish length varied between 119 and 230 mm. They were specifically found attached to the gill chambers and no damage observed in the lamellar pattern.

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Spatial distribution patterns of the sponge-dwelling gnathiid isopod Elaphognathia cornigera (Nunomura) on an intertidal rocky shore of the Izu Peninsula, southern Japan

Cited by 13 publications

References 10 publications

Life history of gnathiid isopods-current knowledge and future directions

Life history of gnathiid isopods-current knowledge and future directions

Diurnal activity patterns of the temporary fish ectoparasite,Gnathia africanaBarnard, 1914 (Isopoda, Gnathiidae), from the southern coast of South Africa

First record of Gnathia sp. an ectoparasitic isopod isolated from the coral reef fish, Heniochus acuminatus collected from the Gulf of Mannar region, southeast coast of India

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