family rhinidae wedgefishes /guitarfishes

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Family Rhinidae dgefishes /Guitarfish

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Family Rhinidae Wedgefishes /Guitarfishes. Taxonomy. Order Rhiniformes (or Rajiformes?) Family Rhinidae (or Rhynchobatidae?) Genus Rhynchobatus R. djidennsis (giant guitarfish)* R.australiae (white-spotted guitarfish) R. laevis (smoothnose wedgefish) - PowerPoint PPT Presentation

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Page 1: Family Rhinidae Wedgefishes /Guitarfishes

Family RhinidaeWedgefishes /Guitarfishes

Page 2: Family Rhinidae Wedgefishes /Guitarfishes

Taxonomy

Order Rhiniformes (or Rajiformes?)

Family Rhinidae (or Rhynchobatidae?)

Genus Rhynchobatus

R. djidennsis (giant guitarfish)* R.australiae (white-spotted guitarfish) R. laevis (smoothnose wedgefish) R. leubberti (African wedgefish) R. spp. nov. A (roughnose wedgefish) R. spp. nov. B (broadnose wedgefish)

Page 3: Family Rhinidae Wedgefishes /Guitarfishes

Morphology

seem to be intermediate between Pristidae and Rhinobatidae

elongated rostrum (without saw)

large, shark-like fins- 2 dorsal

batoid-like cephalic pectoral fins

Page 4: Family Rhinidae Wedgefishes /Guitarfishes

Morphology

dorsoventrally flattened

large spiracles near the eyes

size: TL ~300cm

R. australiae- color morphs in Indonesiadifferent species?

undescribed spp.A- “dwarf” species- 82cm TL

Page 5: Family Rhinidae Wedgefishes /Guitarfishes

Habitat and Distribution

Most: Indo-West-Pacific, especially IndonesiaR. luebberti- E. Atlantic

all species are inshore, coastal, usually ~35m deep

found near sandy beaches (KwaZulu-Natal, S. Africa) and along reef edges

Page 6: Family Rhinidae Wedgefishes /Guitarfishes

Reproduction

mature at 150cm TL, 60cm TL at birth

aplacental viviparous

~4 pups/litter

R. australiae- up to 19 pups/litter

probably low fecundity due to typical elasmo life history characteristics

Page 7: Family Rhinidae Wedgefishes /Guitarfishes

Prey

stomach contents: crab, bivalve molluscs

Page 8: Family Rhinidae Wedgefishes /Guitarfishes

Conservation

habitat destruction

bycatch (prawn fishery, Indonesia and KwaZulu-Natal)

Page 9: Family Rhinidae Wedgefishes /Guitarfishes

Conservation

targeted fisheries (fins, meat, Indonesia, Tanzania)probably among most highly desired chondrichthyans

high value fins, highly palatable meat

Page 10: Family Rhinidae Wedgefishes /Guitarfishes

Conservation

easily caught in bottom set gillnets, bottom trawls

Page 11: Family Rhinidae Wedgefishes /Guitarfishes

Conservation

“protective” shark nets (KwaZulu-Natal)- but many released alive

life history characteristics

females caught more than males

Page 12: Family Rhinidae Wedgefishes /Guitarfishes

Conservation

IUCN Redlist: all species vulnerable, R. leubberti- endangered (W. Africa)

likely to see decreasing trends due to limited distribution, continuation of unregulated fishing

Page 13: Family Rhinidae Wedgefishes /Guitarfishes

Literature CitedCompagno, L.J.V. & Marshall, A.D. 2006. Rhynchobatus luebberti. In: IUCN 2007. 2007 IUCN Red List of

Threatened Species. <www.iucnredlist.org>. Downloaded on 04 November 2007. Compagno, L.J.V. & Marshall, A.D. 2006. Rhynchobatus sp. nov. A. In: IUCN 2007. 2007 IUCN Red List of

Threatened Species. <www.iucnredlist.org>. Downloaded on 04 November 2007. Compagno, L.J.V. & Marshall, A.D. 2006. Rhynchobatus sp. nov. B. In: IUCN 2007. 2007 IUCN Red List of

Threatened Species. <www.iucnredlist.org>. Downloaded on 04 November 2007. McAuley, R. & Compagno, L.J.V. 2003. Rhynchobatus laevis. In: IUCN 2007. 2007 IUCN Red List of

Threatened Species. <www.iucnredlist.org>. Downloaded on 04 November 2007. McEachran, J.D. and N. Aschliman. 2004. Phylogeny of Batoidea. Pp. 79-114 in Biology of Sharks and

Their Relatives (J.C. Carrier, J.A. Musick, and M.R. Heithaus, eds). CRC Press, Boca Raton.

Stobutzki, I.C., M.J. Miller, D.S. Heales, and D.T. Brewer. 2002. Sustainability of elasmobranchs caught asbycatch in a tropical prawn (shrimp) fishery. Fish. Bull. 100: 800-821.

 White, W.T. and Dharmadi. 2007. Species and size compositions and reproductive biology of rays

(Chondrichthyes, Batoidea) caught in target and non-target fisheries in eastern Inodnesia.J. Fish Biol. 70: 1809-1837

 White, W.T. & McAuley, R. 2003. Rhynchobatus australiae. In: IUCN 2007. 2007 IUCN Red List of

Threatened Species. <www.iucnredlist.org>. Downloaded on 04 November 2007.