Effects Of Macroalgae Research Articles

Captive spawning, early development, and larviculture of largescale blackfish, Girella punctata (Gray, 1835), and effects of macroalgae and alternative protein sources on its juvenile growth performance

The largescale blackfish, Girella punctata (Gray, 1835), inhabits rocky substrates in the coastal waters of Japan and northeastern Taiwan. Despite its commercial significance, there is limited knowledge regarding its reproductive biology due to the sparse occurrence of broodstocks in its natural environment. This study investigated the reproductive performance and embryonic development of G. punctata, assesses its feeding preferences through controlled feeding trials, and evaluates the impact of various feed types on its growth performance. In total, 124 wild-caught G. punctata were reared for 3–4 years, and their reproductive performance was assessed in 2015 and 2016. Their egg production increased with a sudden water temperature change from 17 ℃ in 2015–22 ℃ and 2016. The total and daily average egg production weights were 3589.22 and 40.79 g, respectively, whereas the total and daily average fertilized egg production weights were 1630.72 and 18.59 g, respectively; moreover, the hatching rate was 42.61 %. During embryonic development, the eggs hatched 45 h post fertilization at 19 ℃. Newly hatched larvae were 2.26 ± 0.04 mm in length with a yolk sac of 1.09 ± 0.02 mm in length. The yolk sac was almost completely absorbed 3 days post hatch (dph), when the larvae grew to a length of 3.42 ± 0.06 mm. We found that fish meal with 40 % protein was the optimal G. punctata fish diet. The weight gain in juveniles fed Cladophora fascicularis ranged from 47 % to 52 %, which was significantly higher than that in those fed Hypnea charoides (p < 0.05). The present study provided a practical guideline on the conditions required for successful fertilization and early development of G. punctata embryos and other larval stages. This information should help ensure greater survival and a higher proportion of healthy G. punctata larvae for mariculture applications.

Effects of macroalgae and sea urchin grazing pressure on zoantharians growth under laboratory conditions

In the context of ocean warming, thermophilic organisms such as zoantharians are expanding and altering shallow benthic habitats. Here, a four-month laboratory experiment was performed to examine the influence of three types of macroalgae morphotypes common in the Canary Islands (turf algae, Lobophora spp., and crustose coralline algae) on the growth of two zoantharian species, Palythoa caribaeorum and Zoanthus pulchellus. Additionally, the grazing effects of echinoids Diadema africanum and Paracentrotus lividus were assessed as facilitators of substrate colonization by means of controlling macroalgae cover. Colony and algal coverages were measured at the beginning, middle and end of the experiment, and increments were calculated. Results indicated a general decrease in zoantharian colony sizes in contact with different algal types in the absence of sea urchins. However, P. caribaeorum colonies showed significant growth in the presence of D. africanum, highlighting the ecological importance of sea urchins in zoantharian population proliferation and subsequent community modification. This study represents the first investigation into zoantharian-macroalgae interactions under controlled conditions.

Effect of macroalgae as a functional ingredient in grow-out diets on the biological performance, digestive capacity, and immune response of totoaba, Totoaba macdonaldi

Effect of macroalgae as a functional ingredient in grow-out diets on the biological performance, digestive capacity, and immune response of totoaba, Totoaba macdonaldi

Carotenoid Accumulation in Common and Orange-Muscle Mutant of Abalone, Haliotis gigantea, Fed with Different Macroalgae

Aquatic animals cannot synthesize carotenoids, thus they must come from diet or from symbionts. Previous studies have found that orange-muscle abalones are rich in carotenoids, but the effects of different diets on the accumulation of carotenoids are unknown. In this study, the effects of macroalgae (Gracilaria lemaneiformis), fresh and dried kelp (Laminaria japonica) on the contents of the predominant carotenoids, including zeaxanthin, β-carotene, and fucoxanthin, between the common and orange-muscle mutant of Haliotis gigantea were compared through a one-year culture experiment. Our study confirmed that carotenoids in abalones mainly come from diets, and the carotenoid types in the muscles were similar to their diets. We also found that feeding on G.lemaneiformis played an important role in maintaining a stable carotenoid content over time, especially zeaxanthin in H.gigantea. Our data also provided that abalones had a good growth performance under the feeding conditions of G.lemaneiformis. Finally, compared with common abalones, orange-muscle abalones had a notably enhanced ability to accumulate carotenoids through their diet, especially zeaxanthin ( P &lt; 0.01 ). However, the growth performance of orange-muscle abalones was lower than those of common abalones fed the same diets. These results inferred that the content of carotenoid in abalone may be controlled by genetic factors, and diet had a significant influence on the accumulation of carotenoid in abalone to some extent.

Macroalgae composition alters occupancy of multiple bird guilds in rocky intertidal communities

In the north Atlantic, rocky intertidal shores with diverse macroalgal assemblages are common. Despite this, the effect of macroalgae on bird use of these habitats is not well understood. We used a single-season, single-species occupancy framework to investigate the influence of the macroalgal assemblage on 3 bird guilds and 2 single-species groups: shorebirds (waders), scavengers, divers, common eiderSomateria mollissimanon-parenting adults, and common eider broods. In particular, we considered whether bird occupancy is more strongly determined by the taxonomic composition of the macroalgal assemblage or by structural characteristics of the collective assemblage. We conducted avian point counts and intertidal habitat surveys at 75 sites along the Maine (USA) coast in 2016 and 2017. Macroalgae increased the probability of site occupancy for 1 guild and 2 single-species groups. Most notably, we found that shorebird occupancy had a positive relationship with the spatial extent and mat depth ofAscophyllum nodosum, indicating a preference for more homogeneous and deeper macroalgal assemblages dominated by this common, tall-canopied taxon. In contrast, common eider presence had a positive relationship with the spatial extent of 2 categories of shorter-canopied macroalgae that are less dominant members of the macroalgal assemblage. Both shorebirds and eiders were less likely to occur in areas with steeper intertidal slopes, which provide less potential habitat during low tides. Overall, our results suggest that macroalgae composition and availability influences bird occupancy in rocky intertidal habitats, but more mechanistic studies (e.g. behavioral) are needed to understand the exact role macroalgae play in coastal bird ecology.

Effects of macroalgae on coral fecundity in a degraded coral reef system

Global declines in live coral cover and the proliferation of macroalgae on coral reefs is leading to increased coral-macroalgal interactions that impact reef recovery. However, the effects of macroalgae on coral sexual reproduction—a fundamental life-history process for maintaining population abundances—have rarely been quantified. Here, we examined the direct effects of macroalgae contact on the fecundity (eggs mesentery−1) of two coral species, Echinopora lamellosa and Merulina ampliata, across three degraded reefs in Singapore. Increasing macroalgae contact from 5% to 25% significantly reduced fecundity in colonies of both species by 67–82%, and also reduced M. ampliata egg sizes by 11.4%. These results suggest the diversion of energy from reproduction towards other processes such as repair and defence, and also reveal potential differential energy allocation strategies among coral taxa. While corals on Singapore's impacted reefs continue to produce eggs, increasing macroalgae that suppresses coral fecundity may constrain future reef recovery.

大型海藻在珊瑚礁退化过程中的作用

大型海藻在珊瑚礁退化过程中的作用

Effects of macroalgae on the recruitment, growth, and body condition of an invasive reef forming polychaete in a south-western Atlantic coastal lagoon

Species interactions could mediate species invasive processes. In Mar Chiquita coastal lagoon (37° 40′S, 57° 23´W, Argentine), the invasive reef building polychaete Ficopomatus enigmaticus (Fauvel 1923) enhances the biomass of the red alga Polysiphonia subtilissima Montagne 1840 on reef surfaces, and excludes green macroalgae (mainly Cladophora sp. Kützing, 1843) from sediment between reefs. In turn, macroalgae could have several community structuring effects (e.g., as food or by competing for space). Therefore, macroalgae may affect F. enigmaticus. To evaluate this hypothesis we studied (1) the interaction between macroalgae and F. enigmaticus during the colonization of new substrates and (2) the effects of macroalgae on the recruitment, growth, and body condition of F. enigmaticus. Field sampling and experiments suggested a lack of competition on new substrates. However, there was a positive effect of macroalgae on F. enigmaticus during the warm season, since its recruitment, tube length, and body condition were higher in areas with macroalgae on reef surfaces. Considering that previous studies showed that reefs positively affect macroalgae, our results suggest that there is a positive feedback on F. enigmaticus created by macroalgae on established reefs and during the reefs' growing season. This interaction may contribute to the maintenance and growth of established reefs.

Variability in the Effects of Macroalgae on the Survival and Growth of Corals: The Consumer Connection

Shifts in dominance from corals to macroalgae are occurring in many coral reefs worldwide. Macroalgal canopies, while competing for space with coral colonies, may also form a barrier to herbivorous and corallivorous fish, offering protection to corals. Thus, corals could either suffer from enhanced competition with canopy-forming and understorey macroalgae or benefit from predator exclusion. Here, we tested the hypothesis that the effects of the brown, canopy-forming macroalga, Turbinaria ornata, on the survival and growth of corals can vary according to its cover, to the presence or absence of herbivorous and corallivorous fish and to the morphological types of corals. Over a period of 66 days, two coral species differing in growth form, Acropora pulchra and Porites rus, were exposed to three different covers of T. ornata (absent versus medium versus high), in the presence or absence of fish. Irrespective of the cover of T. ornata, fish exclusion reduced mortality rates of A. pulchra. Following fish exclusion, a high cover of T. ornata depressed the growth of this branched coral, whilst it had no effect when fish species were present. P. rus suffered no damage from corallivorous fish, but its growth was decreased by high covers of T. ornata, irrespective of the presence or absence of fish. These results show that negative effects of T. ornata on some coral species are subordinate to those of fish predation and are, therefore, likely to manifest only on reefs severely depleted of predators. In contrast, space dominance by T. ornata may decrease the growth of other coral species regardless of predation intensity. In general, this study shows that susceptibility to predation may determine the severity of the effects of canopy-forming macroalgae on coral growth.

Effects of macroalgae on corals recovering from disturbance

Corals have an ability to recover from disturbance through the regeneration of tissue, but macroalgae are believed to impede this process. In this study, the type of benthic macroalgae deposited on coral skeleton was manipulated experimentally, and the effects on tissue regeneration and skeletal growth of two common coral species Acropora pulchra and Acropora aspera were observed after disturbance. Macroalgae, common to the study region, but from variable functional groups, were investigated for their influence on coral growth. The green filamentous macroalga Chlorodesmis fastigiata significantly reduced tissue recovery in A. pulchra, but not in A. aspera. It led to the infection of A. pulchra with ciliates. The brown seaweed, Lobophora variegata, the encrusting coralline alga Porolithon (= Hydrolithon) onkodes, and turf algae, had only minor effects on coral recovery. This suggests that the outcome of the regeneration process is highly variable and dependent upon both, the species of coral and algae involved.

Polyculture of the lined seahorse, Hippocampus erectus Perry, 1810 with two species of macroalgae in aquaria

A two-month study was conducted to test the effects of macroalgae on the growth and survivorship of juvenile lined seahorse (Hippocampus erectus) in aquaria. Twenty-day old seahorses were cultured in the tanks with green alga Chaetomorpha linum, red alga Gracilaria tikvahiae, green plastic artificial plant (stargrass), and black plastic net, respectively. Increases in wet mass and standard length for the seahorses were significantly higher in the tanks with macroalgae than those without macroalgae. The seahorse survivorships in the two macroalgal treatments were also significantly higher than those of the two treatments without macroalgae. In the treatments with macroalgae, the DO and pH were higher than those without marcoalgae. During the experiment, the color of seahorses was changed to certain extent. In the green background (the treatments with C. linum and stargrass), 24.1%–28.4% of black seahorses decreased over time; whereas in the black (plastic net) or brown (G. tikvahiae) background treatments, 14.1%–16.3% of yellow seahorses decreased over time, for matching that of the background. Furthermore, the survival rate of seahorse was correlation with DO and pH, and strong correlation with standard length, wet mass and CF. Polyculture with macroalgae, survival rates of seahorse were higher than without macroaglae.

The characteristics of nutrient removal and inhibitory effect of Ulva clathrata on Vibrio anguillarum 65

To investigate the ecological effect of macroalgae on de-eutrophication and depuration of mariculture seawater, the variation of dissolved inorganic nitrogen (DIN) and phosphate (DIP), the amount of Vibrio anguillarum, and total heterotrophic bacteria in Ulva clathrata culture, as well as on the algal surface, were investigated by artificially adding nutrients and V. anguillarum strain 65 from February to April 2006. The results indicated that U. clathrata not only had strong DIN and DIP removal capacities, but also showed a significant inhibitory effect on V. anguillarum, although not reducing the total heterotrophic bacteria. Vibrio anguillarum 65 dropped from 5∼8 × 107 cfu mL−1 to 10 cfu mL−1 (clone-forming units per mL) in 10 g L−1 of fresh U. clathrata culture within 2 days; i.e., almost all of the Vibrios were efficiently eradicated from the algal culture system. Our results also showed that the inhibitory effect of U. clathrata on V. anguillarum strain 65 was both DIN- and DIP-dependent. Addition of DIN and DIP could enhance the inhibitory effects of the algae on the Vibrio, but did not reduce the total heterotrophic bacteria. Further studies showed that the culture suspension in which U. clathrata was pre-cultured for 24 h also had an inhibitory effect on V. anguillarum strain 65. Some unknown chemical substances, either released from U. clathrata or produced by the alga associated microorganisms, inhibited the proliferation of V. anguillarum 65.

Influence of macroalgal mats on abundance and distribution of dunlin Calidris alpina in estuaries: a long-term approach

Estuaries used by shorebirds during the non-breeding season face many types of human pressure, including eutrophication and consequent occurrence of macroalgal blooms. The impact of this phenomenon on the abundance of dunlin Calidris alpina in the Mondego estuary, Portugal, was explored using long-term, monthly time series, between 1993 and 2003. The data series included total macroalgal cover, macroinvertebrate biomass and dunlin abundance. We observed an increase in dunlin abundance during this period that matched the decrease in macroalgal cover, especially since the promotion of management actions in 1998. We suggest that this increase was related to the increase of some of its main prey species, the polychaete Hediste diversicolor and the bivalve Scro- bicularia plana. At smaller scales, no effect of macroalgae was observed on the proportion of dunlin that chose to feed in alternative habitats (salinas) during the low tide period. However, there was a small effect of the level of algal cover on the proportion of birds recorded on macroalgae at interme- diate levels of coverage (around 25% of total mudflat area).

Macroinvertebrate response to different species of macroalgal mats and the role of disturbance history

Over the last 20 years, the Mondego estuary, Portugal has experienced excessive growth of macroalgae especially in the inner parts of the system, with several algal species implicated. In this study, we compare the effects of morphologically different species, the red alga Gracilaria verrucosa and the green macroalga Enteromorpha intestinalis on macrobenthic assemblages, by a field experiment whereby the biomass of algae was manipulated and the resultant changes in macrofauna abundance evaluated. The experiments were carried out in different areas (a relatively undisturbed sea grass bed and an upstream eutrophic area) experiencing different degrees of overall enrichment. Measurements of sediment redox potential revealed a rapid anoxia with a significant increase in algal biomass after 4 weeks. The effects of macroalgae were different at the two sites, being more marked in the eutrophic area. In addition, the effects of Gracilaria and Enteromorpha were significantly different, with Enteromorpha having a greater detrimental effect for most of the macrofauna, in particular Cyathura carinata, Scrobicularia plana, Cerastoderma edule and Alkmaria romijni. However, three of the most abundant invertebrates ( Hydrobia ulvae, Hediste diversicolor and Capitella capitata) showed significant increases in abundance in weed affected compared to weed-free plots. Gracilaria had less of an impact on macrobenthic assemblages leading to a more enriched community. Between-site differences in overall impact were related to their previous disturbance history.

Habitat structure, resources and diversity: the separate effects of surface roughness and macroalgae on stream invertebrates.

Habitat structure has pervasive effects on community composition and diversity, with physically complex habitats often containing more species than physically simple ones. What factors or mechanism drive this pattern is little understood, but a complicating problem is that different sources of habitat structure can be confounded in both surveys and experiments. In this study, we carried out an experiment in which two sources of habitat structure, attached macroalgae and substrate surface texture, were separately manipulated to discern their joint and separate effects upon the diversity and composition of colonizing macroinvertebrates in a stony, upland stream. Because stream algae vary markedly in abundance in both space and time, we also sampled the epilithon of stream stones at two spatial scales on eight dates over 2 years to gain some preliminary data on how stream algae vary between individual substrata over time. Experimental substrata had either a smooth (siltstones, sandstones, crystal-poor felsic volcanics, plain paving bricks) or rough (granodiorites, crystal-rich felsic volcanics, sand-blasted paving bricks) surface. We allowed these substrata to be colonized naturally by macroalgae, mostly the filamentous red alga Audouinella hermannii. Half of each of the rough and smooth substrata were selected at random and the macroalgae gently sheared off. All substrata were defaunated with a household insecticide with little field persistence, set out randomly through the study riffle, and invertebrates allowed to colonize them for 14 days. Some substrata were sampled immediately to check the efficacy of faunal and algal removals, which proved to be successful. Experimental results showed that both surface texture and macroalgae increase species richness independently of each other. Surface texture had no effect on densities, while macroalgae increased colonization densities, but rarefaction showed that both sources of habitat structure increased species richness above values expected simply on the basis of the numbers of colonists. However, reference stones with high macroalgal cover had the same species richness as those with low cover, suggesting that the effects of macroalgae on species richness are transient relative to those associated with surface texture. Epilithon samples taken at different times suggest that the magnitude of spatial variation in plant growth alters with time. If plants generally recolonize rough surfaces more quickly than smooth, then the effects of habitat structure on macroinvertebrates ought to be strongest after major disturbances during growing seasons of plants.

Effects of macroalgae and biofilm on settlement of blue mussel (Mytilus edulis l.) larvae

Marine macroalgae are covered by a biofilm community of bacteria and diatoms. In this study, the influences of macroalgae and their biofilm community on the settlement and behaviour of epibionts such as the blue mussel were examined. Under field conditions (White Sea, Kandalakshsky Gulf), larvae of Mytilus edulis settled predominantly on thalli of the filamentous green algae Cladophora rupestris compared to thalli of the brown macroalgae Laminaria saccharina and Fucus vesiculosus. In laboratory experiments biofilm and wash‐outs from C. rupestris attracted larvae while those from L. saccharina repelled blue mussel larvae. Biofilm and wash‐outs from F. vesiculosus had no behavioral effect on the larvae. In general, biofilm had the same effect on the behaviour of the larvae as the macroalgae themselves. Field experiments which were designed to decrease flow around substrates also demonstrated that thalli of C. rupestris attracted larvae, but those of L. saccharina repelled them. It is concluded that macroalgae and biofilm affect substrate selection by blue mussel larvae, both by excretion of signals (repellents or attractants) and toxic substances.

Effects of Macroalgae, Night and Day, on Ammonium Profiles in Waquoit Bay.

Effects of Macroalgae, Night and Day, on Ammonium Profiles in Waquoit Bay.

Effects of Macroalgae on a Stream Invertebrate Community

The effects of macroalgae on stream invertebrates were studied in riffle zones in a coastal southern California stream. Dense growths of macroalgae (Cladophora glomerata, Nostoc sp.) were experimentally removed at different times of the year and in different years, and the insect communities which developed were compared with those in unmanipulated controls. Marl precipitated by algae was also removed in one experiment. The presence of macroalgae was associated with greater total densities and taxon richness of invertebrates, and nearly all taxa responded significantly to algal removal on at least some dates. Insects formed most of the community and were classified according to three categories of macroalgal effects on benthic densities: 1. Negatively affected by macroalgae (and marl) due to competition for space--e.g., Blepharicera (strong response to both algal taxa); large Simulium (strong with Cladophora, weak with Nostoc). 2. Positively affected due to structural habitats created by algae--e.g., Micr...