Food web constraints on larval growth in subtropical coral reef and pelagic fishes

2020 ◽  
Vol 650 ◽  
pp. 19-36 ◽  
Author(s):  
MR Gleiber ◽  
S Sponaugle ◽  
KL Robinson ◽  
RK Cowen
Keyword(s):  
Coral Reef ◽  
Prey Availability ◽  
Interactive Effect ◽  
Larval Growth ◽  
Additive Models ◽  
Fish Growth ◽  
Effect Of Temperature ◽  
Fine Scale ◽  
Recent Growth ◽  
Background Density

Prey availability and predation pressure are thought to be key constraints on larval growth, especially in low-productivity, subtropical environments. Yet, measuring their effects on larval fishes has been challenging, given the dynamic biophysical drivers of plankton distributions and small scales of interactions. We integrated fine-scale net tows (10s of meters) with in situ imaging to explore how predator-prey interactions influence larval fish growth in the Straits of Florida. Otolith-derived recent growth was analyzed for 3 ecologically important fishes: 2 coral reef labrids (Thalassoma bifasciatum and Xyrichtys novacula) and 1 tuna (Katsuwonus pelamis), with differing mean growth rates (labrids 0.25 mm d-1, K. pelamis 0.44 mm d-1) and prey (labrids-copepods; tuna-appendicularians). We used generalized additive models to examine the interactive effect of background density and frequency of elevated (>2 SD above background) prey and predators on recent (last 3 d) larval growth. For all taxa, recent growth increased with prey background density. Recent growth of labrids was also higher when copepod densities were more often elevated (14% of transect >20 ind. m-3) above otherwise low background densities (2 ind. m-3). Predators (chaetognaths and hydromedusae) had a growth-selective effect: stronger selection in transects with high-density predator patches, although the direction of the effect was species-specific. The effect of temperature was taxa-specific: growth increased with temperature for the labrids and peaked at an optimum (28°C) for the rapidly growing tuna. Integration of these fine-scale sampling methods improves our understanding of the variable influence of prey and predators on larval growth and, consequently, larval survival.

scholarly journals Do models parameterized with observations from the system predict larval yellow perch (Perca flavescens) growth performance better in Lake Erie?

2018 ◽  
Vol 75 (1) ◽  
pp. 82-94
Author(s):  
Jose R. Marin Jarrin ◽  
Timothy B. Johnson ◽  
Stuart A. Ludsin ◽  
Julie M. Reichert ◽  
Kevin L. Pangle
Keyword(s):  
Growth Performance ◽  
Yellow Perch ◽  
Lake Erie ◽  
Prey Availability ◽  
Larval Growth ◽  
Perca Flavescens ◽  
Mechanistic Modeling ◽  
Fish Growth ◽  
Western Lake ◽  
Western Lake Erie

Growth performance can influence survival during early life. As such, a range of statistical to mechanistic modeling approaches has been used to predict growth performance, with few studies evaluating prediction accuracy. We tested the ability of three models to estimate observed larval yellow perch (Perca flavescens) growth and length in western Lake Erie (United States – Canada). We found that a general linear model developed using yellow perch data from western Lake Erie performed best followed closely by a semimechanistic individual-based model (IBM) specific to Lake Erie yellow perch and worse by a general multispecies IBM. We suspect that the statistical model performed better because, unlike IBMs, it does not require prey availability data, probably poorly represented by zooplankton samples, and because the IBMs are imperfectly parameterized. Our findings indicate that caution should be exercised when using general IBMs given that the models parameterized with observations from the system of interest outperformed the general IBM in providing accurate fish growth and length estimates, pointing to the need for research that can improve existing mechanism-based models of larval growth.

scholarly journals A three dimensional, full life cycle, anchovy and sardine model for the North Aegean Sea (Eastern Mediterranean): Validation, sensitivity and climatic scenario simulations

2021 ◽  
Vol 22 (3) ◽  
pp. 653
Author(s):  
ATHANASIOS GKANASOS ◽  
EUDOXIA SCHISMENOU ◽  
KOSTAS TSIARAS ◽  
STYLIANOS SOMARAKIS ◽  
MARIANNA GIANNOULAKI ◽  
...  
Keyword(s):  
Temperature Increase ◽  
Eastern Mediterranean ◽  
Larval Growth ◽  
Somatic Growth ◽  
Aegean Sea ◽  
Fish Growth ◽  
Prey Concentration ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

We present the development of a 3D full-lifecycle, individual-based model (IBM) for anchovy and sardine, online coupled to an existing hydrodynamic/biogeochemical low-trophic level (LTL) model for the North Aegean Sea. It was built upon an existing 1D model for the same species and area, with the addition of a horizontal movement scheme. In the model, both species evolve from the embryonic stage (egg+yolk sac larva) to the larval, juvenile, and adult stages. Somatic growth is simulated with the use of a “Wisconsin” type bioenergetics model and fish populations with an adaptation of the ‘super individuals’ (SI) approach. For the reference simulation and model calibration, in terms of fish growth and population biomass, the 2000-2010 period was selected. Interannual biomass variability of anchovy was successfully represented by the model, while the simulated biomass of sardine exhibited low variability and did not satisfactorily reproduce the observed interannual variability from acoustic surveys. The spatial distribution of both species’ biomass was in relatively good agreement with field data. Additional single-species simulations revealed that species compete for food resources. Temperature sensitivity experiments showed that both species reacted negatively to a temperature increase. Anchovy, in particular, was more affected since its spawning and larval growth periods largely overlap with the period of maximum yearly temperature and low prey concentration. Finally, simulation experiments using IPCC climatic scenarios showed that the predicted temperature increase and zooplankton concentration decrease in the future will negatively affect anchovy, resulting in sardine prevalence.

scholarly journals Impact of climate and moonlight on a venomous mammal, the Javan slow loris (Nycticebus javanicus Geoffroy, 1812)

2014 ◽  
Vol 83 (4) ◽  
pp. 217-225 ◽  
Author(s):  
Eva Johanna Rode-Margono ◽  
K. Anne-Isola Nekaris
Keyword(s):  
Climatic Factors ◽  
Prey Availability ◽  
Interactive Effect ◽  
Weather Conditions ◽  
Climatic Conditions ◽  
Activity Level ◽  
Environmental Data ◽  
Foraging Efficiency ◽  
Slow Loris ◽  
Reduce Activity

Predation pressure, food availability, and activity may be affected by level of moonlight and climatic conditions. While many nocturnal mammals reduce activity at high lunar illumination to avoid predators (lunarphobia), most visually-oriented nocturnal primates and birds increase activity in bright nights (lunarphilia) to improve foraging efficiency. Similarly, weather conditions may influence activity level and foraging ability. We examined the response of Javan slow lorises (Nycticebus javanicus Geoffroy, 1812) to moonlight and temperature. We radio-tracked 12 animals in West Java, Indonesia, over 1.5 years, resulting in over 600 hours direct observations. We collected behavioural and environmental data including lunar illumination, number of human observers, and climatic factors, and 185 camera trap nights on potential predators. Nycticebus javanicus reduced active behaviours in bright nights. Although this might be interpreted as a predator avoidance strategy, animals remained active when more observers were present. We did not find the same effect of lunar illumination on two potential predators. We detected an interactive effect of minimum temperature and moonlight, e.g. in bright nights slow lorises only reduce activity when it is cold. Slow lorises also were more active in higher humidity and when it was cloudy, whereas potential predators were equally active across conditions. As slow lorises are well-adapted to avoid/defend predators by crypsis, mimicry and the possession of venom, we argue that lunarphobia may be due to prey availability. In bright nights that are cold, the combined effects of high luminosity and low temperature favour reduced activity and even torpor. We conclude that Javan slow lorises are lunarphobic – just as the majority of mammals.

scholarly journals Interactive effect of temperature and CO2increase in Arctic phytoplankton

2014 ◽  
Vol 1 ◽  
Author(s):  
Alexandra Coello-Camba ◽  
Susana Agustí ◽  
Johnna Holding ◽  
Jesús M. Arrieta ◽  
Carlos M. Duarte
Keyword(s):  
Interactive Effect ◽  
Effect Of Temperature

scholarly journals Fine-scale dietary changes between the breeding and non-breeding diet of a resident seabird

2015 ◽  
Vol 2 (4) ◽  
pp. 140291 ◽  
Author(s):  
Nicole D. Kowalczyk ◽  
André Chiaradia ◽  
Tiana J. Preston ◽  
Richard D. Reina
Keyword(s):  
Prey Availability ◽  
Juvenile Fish ◽  
Fish Communities ◽  
Small Range ◽  
Isotopic Niche ◽  
Fine Scale ◽  
Close Proximity ◽  
Isotope Analyses ◽  
Little Penguin ◽  
Foraging Ranges

Unlike migratory seabirds with wide foraging ranges, resident seabirds forage in a relatively small range year-round and are thus particularly vulnerable to local shifts in prey availability. In order to manage their populations effectively, it is necessary to identify their key prey across and within years. Here, stomach content and stable isotope analyses were used to reconstruct the diet and isotopic niche of the little penguin ( Eudyptula minor ). Across years, the diet of penguins was dominated by anchovy ( Engraulis australis ). Within years, during winter, penguins were consistently enriched in δ 15 N and δ 13 C levels relative to pre-moult penguins. This was probably due to their increased reliance on juvenile anchovies, which dominate prey biomass in winter months. Following winter and during breeding, the δ 13 C values of penguins declined. We suggest this subtle shift was in response to the increased consumption of prey that enter the bay from offshore regions to spawn. Our findings highlight that penguins have access to both juvenile fish communities and spawning migrants across the year, enabling these seabirds to remain in close proximity to their colony. However, annual fluctuations in penguin isotopic niche suggest that the recruitment success and abundance of fish communities fluctuate dramatically between years. As such, the continued monitoring of penguin diet will be central to their ongoing management.

Variability in the growth, feeding and condition of barramundi (Lates calcarifer Bloch) in a northern Australian coastal river and impoundment

2015 ◽  
Vol 66 (10) ◽  
pp. 928 ◽  
Author(s):  
D. J. Russell ◽  
F. E. Thomson ◽  
P. A. Thuesen ◽  
T. N. Power ◽  
R. J. Mayer
Keyword(s):  
Prey Species ◽  
Prey Availability ◽  
Juvenile Fish ◽  
Fish Growth ◽  
Lates Calcarifer ◽  
Resource Limited ◽  
Tropical Australia ◽  
Coastal River ◽  
Freshwater River ◽  
River Fish

Lates calcarifer supports important fisheries throughout tropical Australia. Community-driven fish stocking has resulted in the creation of impoundment fisheries and supplemental stocking of selected wild riverine populations. Using predominantly tag–recapture methods, condition assessment and stomach flushing techniques, this study compared the growth of stocked and wild L. calcarifer in a tropical Australian river (Johnstone River) and stocked fish in a nearby impoundment (Lake Tinaroo). Growth of L. calcarifer in the Johnstone River appeared resource-limited, with juvenile fish in its lower freshwater reaches feeding mainly on small aytid shrimp and limited quantities of fish. Growth was probably greatest in estuarine and coastal areas than in the lower freshwater river. Fish in Lake Tinaroo, where prey availability was greater, grew faster than either wild or stocked fish in the lower freshwater areas of the Johnstone River. Growth of L. calcarifer was highly seasonal with marked declines in the cooler months. This was reflected in both stomach fullness and the percentage of fish with empty stomachs but the condition of L. calcarifer was similar across most sites. In areas where food resources appear stretched, adverse effects on resident L. calcarifer populations and their attendant prey species should be minimised through cessation of, or more conservative, stocking practices.

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