Mediterranean Aquaculture in a Changing Climate: Temperature Effects on Pathogens and Diseases of Three Farmed Fish Species

Abstract

Climate change is expected to have a drastic effect on aquaculture worldwide. As we move forward with the agenda to increase and diversify aquaculture production, rising temperatures will have a progressively relevant impact on fish farming, linked to a multitude of issues associated with fish welfare. Temperature affects the physiology of both fish and pathogens, and has the potential to lead to significant increases in disease outbreaks within aquaculture systems, resulting in severe financial impacts. Significant shifts in future temperature regimes are projected for the Mediterranean Sea. We therefore aim to review and discuss the existing knowledge relating to disease outbreaks in the context of climate change in Mediterranean finfish aquaculture. The objective is to describe the effects of temperature on the physiology of both fish and pathogens, and moreover to list and discuss the principal diseases of the three main fish species farmed in the Mediterranean, namely gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax), and meagre (Argyrosomus regius). We will attempt to link the pathology of each disease to a specific temperature range, while discussing potential future disease threats associated with the available climate change trends for the Mediterranean Sea.

Genomic and Biological Profile of a Novel Bacteriophage, Vibrio phage Virtus, Which Improves Survival of Sparus aurata Larvae Challenged with Vibrio harveyi

“…Furthermore, no significant mortalities were detected in the group treated with only the phage suspensions, indicating the safety of Vibrio phage Virtus to the fish larvae. Although gilthead seabream larvae have been used as an in vivo model to study the therapeutic efficacy of the Vibrio phage Virtus, it should be noted that given the importance of this fish species for the Mediterranean aquaculture [109] and the high prevalence of vibriosis caused by V. harveyi [7], the practical usability of Virtus but also similar phages in commercial aquaculture is evident. Of course, there are several issues that remain to be resolved before phage therapy for aquaculture becomes a common practice including regulatory, mass production of phages and resistance development by the bacteria.…”

“…V. harveyi is ubiquitous and usually grows in temperatures above 18 • C, as its optimal temperature is 25 • C [3]. Climate change and the overall rise of the water temperature in the oceans, along with the intensification of aquaculture, favor the increase in vibrios, and hence the vibriosis incidents have increased alarmingly [3][4][5][6][7]. To date, the management of Vibrio infections has relied mostly on antibiotics such as oxytetracycline, flumequine, and ampicillin.…”

Integrated Management Strategies for Viral Nervous Necrosis (VNN) Disease Control in Marine Fish Farming in the Mediterranean

“…The great potential diffusion of virus into wild fish [ 39 ] makes even the potential impact of this infection on wild fish stocks even greater. Furthermore, as the disease in the Mediterranean area is mainly associated with warm temperature, the climate change could increase the impact of the NNV switching asymptomatic infections into clinical outbreaks [ 40 ].…”

What Can Genetics Do for the Control of Infectious Diseases in Aquaculture?

“…Infectious diseases reduce the economic return of aquaculture production and are a serious problem in the management of aquaculture production, particularly where high-density rearing conditions promote the spread of infectious diseases and induce stress and higher disease susceptibility [ 4 ]. In addition, rising global water temperatures and water levels due to climate change threatens aquaculture production and alters disease dynamics [ 5 ].…”