I used to work at a freight forwarding company and have a degree in International Commerce so I can tell you that in this case "shipping side's" should be translated as ***el embarcador / exportador*** since according to the INCOTERMS it would be his responsability to duly inform shipping company / ocean line of said information.

Beware of the difference, the exporter is the Company making the sale to the overseas buyer/importer but normally they ship via a Freight Forwarding Company as is required in most countries around the world. So normally the exporter/seller of an article/commodity does not have direct contact with the shipping company/ocean line/air line, they work via a Freight Forwarding Company precisely because of all the different shipping and logistics needed and involved with each different merchandise/commodity.

So in this case, if there are any special needs due to agreements between the seller/exporter and the buyer/importer or because of the nature of the commodity/product being exported, it would be the responsability of the exporter/shipper to inform the freight forwarder who in turn has the responsability to duly inform the ocean line and the freight forwarder in the country of final destination who will make all necessary arrangements on behalf of the buyer/importer, including informing the ocean line's offices at destination.

For more information just look up INCOTERMS in Google or Wikipedia.

I edited the original text a bit to be more specific. In my opinion the proper translation should be as follows:
Es la responsabilidad del embarcador asegurarse de que tanto el agente de carga tanto como la compañia naviera esten al tanto de los requerimientos internationales, asi como es responsabilidad de las autoridades portuarias de asegurarse de que los mismos esten al tanto de los requerimientos nacionales.

Its english translation would be as follows:
It is the responsability of the shipper to mke sure that the shipping agent/freight forwarder as well as the ocean line are aware of all international requirements, as is the responsability of the port authorities to make these same parties aware of the national requirements.

Hope this helps...