Efficiency and Rate of Yolk Utilization by Developing Embryos and Larvae of the Pacific Sardine <i>Sardinops caerulea</i> (Girard)

The influence of rearing temperature on growth and yolk utilization in embryos and larvae of the summer flounder Paralichthys dentatus has been investigated. Rates of development, growth and yolk conversion efficiencies were determined for embryos and larvae reared at 16' and 21 ' C . Larvae reared at 21 "C completed total yolk absorption sooner than did larvae reared at 16 "C. However, no significant differences were found in total body length, ash-free dry weight or yolk utilization efficiency for larvae from the two groups. The similarity in growth and yolk utilization efficiency for larvae reared at the two temperatures suggests that the physiological mechanisms involved are able to compensate for temperature changes.

Section: Discussionmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

Yolk Utilization in Summer Flounder (Paralichthys dentatus) Embryos and Larvae Reared at Two Temperatures

Johns¹,

Howell²

1980

“…This maximal gross growth efficiency for fish larvae is intermediate in value to the efficiency of yolk utilization by fish embryos and larvae and the gross growth efficiency of juvenile and adult fish. Lasker (1962) Eldridge et al (1977) reported a yolk utilization efficiency of 0.74 for embryos and of 0.44 for larvae of Pacific herring. Similarly, the efficiency of converting yolk for embryos of other organisms is approximately 0.6 (Calow, 1977).…”

Section: Discussionmentioning

confidence: 99%

Relation of growth to ingestion for larvae of Atlantic herring Clupea harengus and other fish

Checkley¹

1984

Larvae of Atlantic herring Clupea harengus were reared on wild plankton and Artemia salina nauplii in the laboratory at 7 to 9OC for 95 d. Between ages of 20 and 38 d, larvae were fed only Artemia nauplii and the specific rates of ingestion and growth were measured and compared. Relations of rate and efficiency of growth to ingestion were similar in terms of carbon and nitrogen. Growth was linearly related to ingestion (r2 = 0.89, n = 9). Starved larvae lost mass at a specific rate of 0.03 d-I (3 % d l ) until death at 14 d. A specific ingestion rate of 0.04 d 1 was required to balance defecation and metabolism. Gross growth efficiency (growth ratehngestion rate) rose from -1.2 at a low ingestion rate (0.015 d l ) to 0.4 at the greatest observed ingestion rate (0.11 d ' ) . Condition factor (dry weight length3) was significantly related to both ingestion rate and length (r2 = 0.69, n = 20). These results, combined with those for other fish larvae, indicate an asymptotic relation between rates of growth and ingestion such that gross growth efficiency is maximal (0.4) at intermediate ingestion rate. Fish larvae surviving in the sea appear to maximize their ingestion rate and thus grow rapidly but with a reduced efficiency.

“…The energy content of a Balanion sp. prey item was estimated to be 0.3 mJ (Finlay & Uhlig 1981, Putt & Stoecker 1989, and that of 1 copepod nauplius to be 7.0 mJ (Lasker 1962, Houde & Schekter 1983.…”

Section: Methodsmentioning

confidence: 97%

“…Older larvae (>10 d post-hatching) fed on a greater range of prey types and sizes that included both nauplii and protozoans (Gallager et al 1996, Hunt von Herbing & Gallager 2000. Protozoans are small (30 to 50 µm), and swim in predictable patterns (Buskey et al 1993), and contain low total amounts of energy (Finlay & Uhlig 1981, Putt & Stoecker 1989, whereas copepod nauplii are larger (80 to 250 µm), swim faster, and provide an order of magnitude more energy than protozoans (Lasker 1962, Houde & Schekter 1983. Hunt von Herbing & Gallager (2000) found that first-feeding larval cod readily perceived and captured protozoans, but seemed less able to capture copepod nauplii because naupliar escape speeds were faster than larval maximal swimming speeds.…”

Section: Introductionmentioning

confidence: 99%

Metabolic costs of pursuit and attack in early larval Atlantic cod

Herbing¹,

Gallager²,

Halteman³

2001

Metabolic costs of pursuit and attack for early larval Atlantic cod (Gadus morhua) feeding on 2 different prey types, a protozoan (Balanion sp.) and a copepod nauplius (Pseudodiaptomis sp.) were estimated from 5 to 20 d post-hatch. Parameters describing feeding patterns were determined from 3-dimensional observations using 2 orthogonal cameras. Feeding parameters were calculated using a digital image-analysis system for larvae in 3 size classes, and included pursuit duration, distance and speed for both burst and glide components, and attack duration, distance and speed. Metabolic rates were estimated for each component of pursuit and attack from the relationship between specific metabolic rate and swimming speed from previous respirometry studies on cod larvae. Estimated specific metabolic rates were used in a new model to determine specific and total energy expenditures, which incorporated each of the components of pursuit and attack. Values of total energy expenditure were used in a model to determine relative net energy gain during pursuit and attack of a larva on a protozoan and a copepod nauplius in 3 larval size classes. In Size Class 1 (5 to 6 mm total length, TL) first-feeding larval cod were small and poorly developed, had long pursuit and attack times and distances, and slow swimming speeds. In Size Classes 2 (6 to 7 mm TL) and 3 (7 to 8 mm TL) larger larvae were better developed, had shorter pursuit and attack times and distances, and faster swimming speeds. Specific metabolic rates during pursuit of a protozoan increased with increasing larval size, while specific energy expenditure decreased due to shorter pursuit times. Results from net energy gain equations showed that a cod larva gained 3 orders of magnitude more energy from consumption of a nauplius than a protozoan even though its energy expenditure during pursuit of a nauplius was 2 to 3 times that during pursuit of a protozoan.