Bluecliffs Beach 2005 toheroa survey : yield per recruit and review of historical surveys.

By: Beentjes, M.P.
Contributor(s): Gilbert, D.J. (NIWA. Wellington).
Material type: materialTypeLabelBookSeries: New Zealand fisheries assessment report ; 2006/37.Publisher: Wellington : Ministry of Fisheries, 2006Description: 48 p. : figs. ; 30 cm.ISSN: 1175-1584.Subject(s): TOHEROA | FISHERY SURVEYS | BLUECLIFFS BEACH | SOUTHLAND | ABUNDANCE | STOCK ASSESSMENTOnline resources: Click here to access online In: New Zealand fisheries assessment reportAbstract: A survey of Bluecliffs Beach toheroa was carried out between 11 and 14 February 2005 with 47 transects being sampled (16 sieved and 31 non-sieved). A two phase ralndom survey design was used with 35 transects in phase 1 and 12 in phase 2. The population estimates were 165 000 legal-sized toheroa (100 mm and over), 51 000 sub-legals (40-99 nun), and 805 000 juveniles (under 40 mm) with c.v.s of 15%,24%, and 10%, respectively. The required survey target c.v. for legal-sized toheroa was 20%. The juvenile population estimate was from sieved transects only. The length frequency distribution was characterised by a strong mode of juvenile toheroa (under 40 mrn), and a less pronounced mode from 110 to 145 mm. with relatively few sub-legal toheroa between these modes. Toheroa were found in all strata, but 80% of adults were within a 1 km stretch of beach directly west of the Rowallan Burn, and juvenile density was highest at the east end of the beach. The size groups occupied different zones betweerl high and low water with mean distance from high water of 90 m for adults, 86 m for sub-legals, and 71 m for juveniles, which have the widest range. Of the 1070 quadrats sampled. 54% had substrate suitable for toheroa (sand or coarse sand).
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Item type Current location Call number Copy number Status Date due Barcode
JOURNAL JOURNAL WELLINGTON
JOURNALS
NO. 2006/37 1 Available J09464

A survey of Bluecliffs Beach toheroa was carried out between 11 and 14 February 2005 with 47 transects being sampled (16 sieved and 31 non-sieved). A two phase ralndom survey design was used with 35 transects in phase 1 and 12 in phase 2. The population estimates were 165 000 legal-sized toheroa (100 mm and over), 51 000 sub-legals (40-99 nun), and 805 000 juveniles (under 40 mm) with c.v.s of 15%,24%, and 10%, respectively. The required survey target c.v. for legal-sized toheroa was 20%. The juvenile population estimate was from sieved transects only. The length frequency distribution was characterised by a strong mode of juvenile toheroa (under 40 mrn), and a less pronounced mode from 110 to 145 mm. with relatively few sub-legal toheroa between these modes. Toheroa were found in all strata, but 80% of adults were within a 1 km stretch of beach directly west of the Rowallan Burn, and juvenile density was highest at the east end of the beach. The size groups occupied different zones betweerl high and low water with mean distance from high water of 90 m for adults, 86 m for sub-legals, and 71 m for juveniles, which have the widest range. Of the 1070 quadrats sampled. 54% had substrate suitable for toheroa (sand or coarse sand).

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