Historical shipwrecks threatened by bottom trawling

Shipwrecks threatened – Underwater cultural heritage needs protection

Shipwrecks are not only important cultural sites but they have become hotspots for marine biodiversity and are therefore important artificial reef habitats. Unfortunately, until recently less attention has been given to the high number of destroyed shipwreck sites. But Shipwrecks are threatened! Scientists investigated 45 shipwrecks out of which 17 are amphora wrecks, in the Mediterranean and the Black Sea and quantified the damage of bottom trawl fishing on them. The study results show that trawling has a clear negative impact on the shipwrecks and/or on the surrounding area. Furthermore, it demonstrates that restricting bottom trawling enforces preservation of shipwrecks and has benefits on the surrounding natural seabed features and benthic habitats. It is of high importance to protect such sites from being destroyed by trawling and coordinated management of fishing activity in shipwreck areas should be included in marine spatial planning to mitigate this destructive activity.

Keywords: bottom trawling, shipwrecks, archeology, underwater cultural heritage
Study area: Mediterranean and Black Sea

Interest on shipwrecks

The interest on shipwrecks is increasing in the past years from both the scientific community and the tourism sector. Scientists are investigating shipwrecks, as they have a high archaeological and historically importance, as well as due to their ability to provide habitat for a diverse biological community. The tourism sector has started to understand that with the right promotion shipwrecks can be utilized as an economic development tool for coastal tourism and maritime heritage.

Studies on human impacts on shipwreck

But studies on the impacts of human activities on shipwreck sites are still limited. The life on and around shipwrecks shows a strong contrast to the surrounding environment because it is made up of species preferring hard substratum. Higher taxa such as sponges, hydroids, sea anemones and bryozoans are growing on shipwrecks and are colorful embellishing them. The fish communities that surround shipwrecks are enriched and the number increased. Therefore, they are often called “biodiversity hotspots” or “oases in the desert”. But shipwrecks are threatened.

Damage caused by bottom trawling on shipwrecks

When mobile fishing gears are towing along the seabed, the destructions are well known. In the case of their impact on shipwrecks and the surrounding area, research is gapping. Scientist investigated the damage caused by bottom trawling on shipwreck areas by quantifying the severity of this threat through repeated visits of 45 shipwrecks, out of which 17 are amphora wrecks, in the Mediterranean and the Black Sea. With the use of side scan sonar scientist were able to acoustically classify shipwrecks and the surrounding area. They found physical damage on shipwrecks and heavy trawling across most of the areas! Shipwrecks are threatened! It is a great challenge to understand and quantify the damages caused by bottom trawling the scientist say.

Urgent need to preserve and protect Maritime heritage

Shipwrecks are archaeological and historical sunken treasures and it is an urgent need to preserve and protect such heritage. Damages caused on shipwreck cannot be repaired. Therefore, monitoring and repeated surveys on shipwrecks are needed to ensure their preservation of shipwrecks and to support the maintenance of our underwater cultural heritage. The scientist of this study state that a “careful marine spatial planning and coordinated management of fishing activity can mitigate this destructive activity.”