Notes on fecundity in the Marine spiny lobster Jasus edwardsii (Hutton) (Crustacea: Decapoda: Palinuridae)

Fecundity in the New Zealand spiny lobster Jasus edwardsii (Hutton) has been investigated by a detailed examination of 14 selected females “in berry” (i.e. carrying external eggs), ranging in carapace lengths from 9.5 cm to 17.0 cm. The following data were obtained for each specimen: (a) the total weight of eggs carried, (b) the average number of eggs per 1 g sample, and (c) the total number of eggs carried.

A positive correlation was noted between the total weight of eggs carried and increase in carapace length. The total weight of eggs carried ranged from 26.9 g in a small specimen of 9.5 cm C.L., to 123.9 g in a large female of 16.0 cm C.L. No relation was found between the average number of eggs per 1 g sample and increase in carapace length. A low count of 3,541 eggs per 1 g sample was recorded, and a high count of 5,005 eggs. A direct relation was noted between the total number of eggs carried by J edwardsii and increase in carapace length. The number of eggs carried ranged from a low figure of about 124,278 in a small specimen of 9.5 cm C.L., to a high figure of about 538,242 in a large female of 17.0 cm C.L. The rate of increase in fecundity was found to be greater in smaller than in larger females of J. edwardsii     

Size at first maturity in females of the spiny lobster jasus verreauxi (Crustacea: Decapoda: Palinuridae)

The carapace length and total length size at first maturity in females of Jasus verreauxi (H. Milne Edwards, 1851) has been investigated by a detailed study of (a) the detection of the smallest size class with external eggs, and (b) the incidence of egg‐carrying females per size‐class interval. For the study 834 females were measured and examined at Spirits Bay, New Zealand, during mid October and late December 1966. The specimens ranged in carapace length from 12.0 cm to 23.9 cm, and in total length from 29.0 cm to 56.9 cm.

The results of the study show clearly that the females reach first maturity at a carapace length or a total length larger than the present minimum legal size, i.e. a carapace length of 10.2 cm (4.02 in.), or a total length of 25.4 cm (10.0 in.). No mature females were found less than 13.5 cm carapace length, or 32.0 cm total length. First maturity was attained by the majority (50% or more) of the J verreauxi females at a carapace length of 15.3 cm or larger, or at a total length of 38.0 cm or larger.

No undersized (smaller than the minimum legal size) females were present in the collections—yet 10.3% of the specimens were found to be immature. Immature females ranged in carapace length from 12.0 cm to 16.9 cm, or in total length from 29.0 cm to 41.9 cm. Being larger than the minimum legal size, all of the immature specimens examined were “harvested"—without having reached first maturity. It appears therefore that the stocks of small, immature female J. verreauxi are not protected by the present New Zealand minimum size regulation.     

Commercial landings of the spiny lobster Jasus edwardsii (Hutton) at Chatham Islands,New Zealand (Crustacea: Decapoda: Palinuridae)

The spiny lobster Jasus edwardsii (Hutton) supports a thriving new fishery at the Chatham Islands, about 770 km east of New Zealand. Commercial fishing for J. edwardsii started in November 1965, and within 2 years the area became a major centre of New Zealand's large spiny lobster fishery, which earned >NZ$5,000,000 in 1967. Over 12 months (September 1966 to August 1967) landings at the Chatham Islands made up 39.8% of the total New Zealand spiny lobster catch of 16,600,0001b.

In the first year of fishing 2,177,923 lb of spiny lobsters were caught, and in the second 7,129,658lb—a 227% increase. Fishing effort also increased substantially: average number of boats fishing each month rose by 174% in the second year, and the total number of boat‐fishing days by 152%. Most specimens of J. edwardsii caught are large and mature, typical of a virgin stock.     

Phyllosoma larvae of Jasus edwardsii (Hutton) (Crustacea: Decapoda: Palinuridae) and their distribution off the east coast of the North Island,New Zealand

The complete series of phyllosoma larval stages of spiny lobster lasus edwardsii are described. Eleven stages are recognised from specimens captured in plankton samples collected along a transect extending 185 km east of Castlepoint, North Island, New Zealand between July 1969 and December 1971. A table of distinguishing characteristics and a key for identification of stages are presented. First stage larvae occur between August and October and last stage larvae about 15 months later. Mortality through the phyllosoma stages is estimated to be 98%. Early stage larvae occur mainly inshore in Southland Current water in the upper 5 m, and later stage larvae occur more frequently offshore in East Cape Current water at 40–60 m depth.