Spatiotemporal and Environmental Dynamics of Abundances and Diversity of Larval Fish in Artificial Reef Edge Habitats of Kitros, Pieria (Northern Aegean Sea, Eastern Mediterranean)

Abstract

Spatiotemporal and physiochemical influences on the abundances and diversity of ichthyoplankton were assessed in the Thermaikos Gulf and edge habitats surrounding the Pieria (Northern Greece) artificial reef complex. The collection of data was performed in edge habitats in the marine protected area near the artificial reef offshore of Kitros. Sampling trips occurred in each season of the spring, summer, and autumn in each year from 2015–2017. This artificial reef complex lies at a distance offshore of 11.5 km from Kitros and the delta of River Aliakmonas. A bongo net sampler was used to sample ichthyoplankton over a network of 16 sampling stations. Seventy species of larval fish were identified. The greatest measures of ichthyoplankton diversity were found during warmer seasons. Non-metric multidimensional scaling showed that seasons play a significant role in species assemblages, as months during the spring, summer, and autumn from different years clustered together. Ten groups of larvae were identified to the family or genus level, such as Arnoglossus spp., Callionymus spp., Crenilabrus spp., Gobius spp., Liza spp., Scorpaena spp., Solea spp., and Spicara spp. Overall, the species with the greatest abundance was the larvae of the European anchovy (Engraulis encrasicolus). The second genera (in order of highest abundance) were Gobius spp. followed by relatively abundant (but lesser numbers of) larvae representing the families Callionymidae, Centracanthidae, and Bothidae. The largest total abundances were found in July 2015 and September 2016. The biodiversity index indicated that measures of diversity were greater in July 2015, which was the only sampling performed in the middle of the summer, and indicated higher diversity in autumn 2015. The aim of this study was to present the assemblages of fish larvae in the marine protected area surrounding the artificial reef of Kitros Pierias as the result of a 3-year sampling program (2015–2017). The novelty of this study is that it is the only study of Ichthyoplankton ever performed in Greece with seasonal repetitions and densely located stations around a coastal marine protected area.

Temporal and Environmental Dynamics of Fish Stocks in the Marine Protected Area of the Artificial Reef of Kitros, Pieria (Northern Greece, Mediterranean Sea)

“…Moreover, temperature is a key factor influencing the spawning season of thermophilic fish species. The role of temperature in species assemblages is also mentioned in previous studies in the same area [13]. The Kitros marine protected area exhibits the hallmark features of a spawning habitat with elevated temperatures, coupled with the presence of nutrients and chlorophyll-a, accounting for significant biovariability in both adult fish and ichthyoplankton assemblages [13] Extended spawning seasons have been observed in the Black Sea, where anchovy ichthyoplankton typically collected from June to September were found from May to October between 2011 and 2016, and Sprattus sprattus larvae, typically found in winter, were detected year-round [34].…”

“…The role of temperature in species assemblages is also mentioned in previous studies in the same area [13]. The Kitros marine protected area exhibits the hallmark features of a spawning habitat with elevated temperatures, coupled with the presence of nutrients and chlorophyll-a, accounting for significant biovariability in both adult fish and ichthyoplankton assemblages [13] Extended spawning seasons have been observed in the Black Sea, where anchovy ichthyoplankton typically collected from June to September were found from May to October between 2011 and 2016, and Sprattus sprattus larvae, typically found in winter, were detected year-round [34]. Another example is the varying spawning season length of the round sardinella due to sea temperature differences between different regions, such as a shorter duration in the northern part of the Western Mediterranean (July-September; ref.…”

“…Correlations with hydrographic data, such as salinity, chl-a, and temperature, sampled in a previous study in the same area [13] were calculated using the Spearman rank coefficient.…”

“…During spring and heading into summer, a seasonal thermocline forms as the daily photoperiod becomes extended and the solar radiation is increasing. Concurrently, in the marine protected area of Kitros, the freshwater input increases, not only because of high rain in autumn but also because of high flow rates in the rivers due to the ice melting from the mountains of the region [13].…”

Catalyzing Conservation: An Analysis of Fish Stock Dynamics in a Marine Protected Area before and after Artificial Reef Deployment

“…Factors, such as photoperiod and solar radiation, contribute to the creation of a thermocline in spring and summer. This period also sees an increased freshwater influx due to higher rainfall and ice melt from regional mountains, affecting water column stratification and river runoff in the area [2]. Moreover, the area is influenced by two primary water bodies: Black Sea Water (BSW) and Levantine Intermediate Waters (LIWs) [3,4].…”